5.1 - 5.10 IP Configuration

-D

Show the list of available interfaces.

-X

Show the packet's contents in both hex and ASCII.

Additional Facts

*You can use the route command on the router to view directly connected routes that have been set up. You can also use it on the default gateway of the local subnet and verify that the router has a route to the remote subnet. Another use of the route command is to view the routing table; this helps you see what networks the router knows about. In addition, the route command can be used to display additional networking information (not provided by ifconfig). One special ping test you can perform is pinging the local host. By doing this, you are verifying that TCP/IP is correctly installed and configured on the local host. In essence, you are finding out if the workstation can communicate with itself. To ping the local host, use the following command: ping 127.0.0.1 If this test fails, check to make sure TCP/IP is correctly configured on the system. *If this test fails, check to make sure TCP/IP is correctly configured on the system.

A host on the network has an IP address of 129.11.99.78 using the default subnet mask. How would you identify the address and mask using CIDR notation?

129.11.99.78/16 Use 129.11.99.78/16 for the address and the mask. With CIDR notation, follow the IP address with a slash (/) and the number of bits in the mask. The default subnet mask for this address is 255.255.0.0, which uses 16 bits in the mask. A mask value of 255.0.0.0 uses 8 bits, and a mask value of 255.255.255.0 uses 24 bits.

Assuming the network is indicated by the default portion of the IP address, which three of the following IP addresses belong to the Class A network 114.0.0.0? (Select three.)

114.122.66.12 114.58.12.0 114.0.0.15 With a Class A network, the first octet indicates the network address. All hosts on the network must have the same value in the first octet (114).

Which of the following are valid IPv6 IP addresses? Select all that apply.

141:0:0:0:15:0:0:1 6384:1319:7700:7631:446A:5511:8940:2552 An IPv6 IP address is a 128-bit address listed as eight 16-bit hexadecimal sections. Leading zeros can be omitted in each section. Therefore, 6384:1319:7700:7631:446A:5511:8940:2552 and 141:0:0:0:15:0:0:1 are both valid IPv6 IP addresses. A single set of all-zero sections can be abbreviated with two colons (::). Therefore, 141::15:0:0:1 is also a valid address. 127.0.0.1 and 192.168.2.15 are IPv4 IP address. 343F:1EEE:ACDD:2034:1FF3:5012 is a 48 bit MAC address.

Your network has been assigned the Class C network address 200.78.151.0. Which of the following addresses can be assigned to hosts on your network? (Select three.)

200.78.151.252 200.78.151.12 200.78.151.111 All hosts on this network must share the first three octets of the IP address (200.78.151). You cannot assign 200.78.151.0 to a host because this address indicates the address of the network. You cannot assign 200.78.151.255 because this address is reserved for the broadcast address.

Top-Level Domain (TLD)

A TLD is the last part of a domain name (for example, .com, .edu, .gov). TLDs are managed by the Internet Corporation of Assigned Names and Numbers (ICANN).

nslookup

A command-line tool used (in Windows and other operating systems) to query the Domain Name System (DNS) to obtain the domain name, the IP address mapping, or for any other specific DNS record.

APIPA

APIPA (Automatic Private IP Addressing) is the Windows function that provides DHCP autoconfiguration addressing. When the DHCP process fails, Windows will automatically assign an IP address from the private range of 169.254.0.1 to 169.254.255.254. Once the address has been assigned, the host uses Address Resolution Protocol (ARP) to verify that the chosen APIPA address is unique.

Automatic Private IP Addressing (APIPA)

APIPA provides an option for automatic IP address assignment without a DHCP server. APIPA is enabled by default on most modern operating systems, including Windows and Linux.

Additional Domains (Second-Level Domains)

Additional domains are second-level domains with names registered to an individual or organization for use on the internet. These names are based on an appropriate top-level domain, depending on the type of organization or geographic location where a name is used. Yahoo.com and microsoft.com are examples of additional domains in your DNS structure.

A Class

Address Range - 1.0.0.0 to 126.255.255.255 First Octet Range - 1-126(00000001-01111110 binary) Default Subnet Mask - 255.0.0.0

-q

Be less verbose (more quiet) with your output.

5.4.2 DHCP Relay Facts

Because a DHCP client doesn't have an IP address assigned when it initially boots, it must use broadcast frames to communicate with a DHCP server. If the server is on a different subnet than the client, then the DHCP requests sent by the client will not reach the server because broadcast frames are dropped by network routers. If your network is configured in this manner, you can implement one of the following mechanisms to forward DHCP broadcasts through network routers to a remote DHCP server on a different subnet:

Obtain an Address from a DHCP Server

Because a DHCP client doesn't have an IP address when it initially boots, it must use broadcast frames to communicate with a DHCP server. The table below describes the method used to obtain an address from a DHCP server.

Auto-configuration

Because hardware IDs are used for node IDs, IPv6 nodes simply need to discover their network IDs. This can be done by communicating with a router.

Built-in Quality of Service

Built-in support for bandwidth reservations makes guaranteed data transfer rates possible. (Quality of service features are available as add-ons within an IPv4 environment but are not part of the native protocol.)

5.1.10 Practice Questions

CIST 1401

5.1.5 Variable Length Subnet Mask (VLSM) Facts

CIST 1401

5.10.5 Practice Questions

CIST 1401

5.2.5 Practice Questions

CIST 1401

5.3.10 Practice Questions

CIST 1401

5.4.5 Practice Questions

CIST 1401

Classful IP Addresses

Classful addresses are IP addresses that use a default subnet mask, as follows: Class A: 255.0.0.0 Class B: 255.255.0.0 Class C: 255.255.255.0

ping

Contacts the DNS server to see if it responds. Be aware that the firewall protecting the DNS server may be configured to drop ICMP packets in order to prevent DoS attacks; if the server doesn't respond, it is not necessarily down. E.X. ping 8.8.4.4

Dynamic DNS (DDNS)

DDNS enables clients or the DHCP server to update records in the zone database. Without dynamic updates, all A (host) and PTR (pointer) records must be configured manually. With dynamic updates, host records are created and deleted automatically whenever the DHCP server creates or releases an IP address lease.

DNS

DNS stands for Domain Name System. The main function of DNS is to translate domain names into IP Addresses, which computers can understand.

-E

Decrypt IPsec traffic by providing an encryption key.

tcpdump -D

Display the list of interfaces TCPdump can listen to.

Ping Host B

If you cannot contact the default gateway router, ping other hosts on the local network. If the pings are successful, check the default gateway router.

dig -x IP address | host IP address

Finds the host name for the queried IP address. E.X. dig -x 62.34.4.72 host 62.34.4.72

Address Resolution Protocol(ARP)

Hosts use ARP to discover the MAC address of a device from its IP address.

Built-in Security Features

IPv6 has built-in support for security protocols such as IPsec. (IPsec security features are available as add-ons within an IPv4 environment.)

DHCP Relay Agent

If you use a Windows server in your network, then you can install the Routing and Remote Access service (RRAS) role on the server and enable the DHCP Relay Agent Role service. The DHCP Relay Agent service sends the DHCP packets it receives to a remote DHCP server on a different subnet. To configure the DHCP Relay service, you must: > Specify which server network interface the agent listens on for DHCP messages. > Specify the IP address of the remote DHCP server the agent should forward DHCP messages to.

Link-local

Link-local addresses (also known as local link addresses) are only valid on the current subnet. Details include the following: > Link-local addresses have an FE80::/10 prefix. This includes any address beginning with FE8, FE9, FEA, or FEB. > All nodes must have at least one link-local address, although each interface can have multiple addresses. > Link-local addresses are used for automatic address configuration, for neighbor discovery, or for subnets that have no routers. *Do not use link-local IPv6 addressing on routed networks. Routers never forward packets destined for link-local addresses to other subnets.

Subnetting Class B Addresses: Default Example

Network Address - 188.50.0.0 Subnet Mask - 255.255.0.0 # of Subnet Addresses - One # of Hosts per Subnet - 65,534 Subnet Address(es) - 188.50.0.0 (only one) Host Address Range(s) - 188.50.0.1 to 188.50.255.254

Ping Host C

Often, the best way to start troubleshooting a problem is to ping the host you are trying to contact. This verifies the reported problem. If the ping is successful, the problem is not related to network connectivity. Check other problems, such as name resolution or service access. *If you have access to another computer, try pinging the destination host from that computer. If the ping is successful, skip the remaining tasks and troubleshoot the local host configuration or physical connection.

-c

Only receive a certain number of packets and then stop.

-S

Print absolute sequence numbers.

nslookup [host]

Queries the IP address of a host. E.X. nslookup www.mit.edu

-e

Retrieve the Ethernet header.

-XX

Same as -X, but also shows the Ethernet header.

nslookup

Starts nslookup in interactive mode. The default interactive mode query is for A records, but you can use the set type= command to change the query type. E.X. nslookup set type=ns

You manage a network that uses IPv6 addressing. When clients connect devices to the network, they generate an interface ID and use NDP to learn the subnet prefix and default gateway. Which IPv6 address assignment method is being used?

Stateless autoconfiguration With stateless autoconfiguration, clients automatically generate an interface ID and learn the subnet prefix and default gateway through the neighbor discovery protocol (NDP). With static full assignment, the entire 128-bit address and all other configuration information is statically assigned. Static partial assignment generates the interface ID from the MAC address, and clients are statically assigned the prefix. Stateful DHCPv6 is when the DHCP server provides each client with an IP address, default gateway, and other IP configuration information.

Which of the following best describes the purpose of using subnets?

Subnets divide an IP network address into multiple network addresses. Subnets divide an IP network address into multiple network addresses. This allows you to have several smaller networks while using only one network address.

5.1.4 Subnet Facts

Subnetting is the process of dividing a large network into smaller networks called subnets. When you subnet a network, each network segment has a different network address, or subnet address. In practice, the terms network and subnet are used interchangeably to describe a physical network segment with a unique network address.

5.9.7 tcpdump Facts

TCPdump is a packet analyzer that runs in a command line utility. It allows the user to view TCP/IP and other packets as they are transmitted and received over on a computer's network. In this lesson, you will learn about: > Common uses > Options > Expression examples

DHCP ACK (A)

The DHCP server responds to the request by sending a DHCP ACK (acknowledgement). At this point, the IP address is leased to and configured on the DHCP client.

Parts of a DNS

The DNS is made up of the following components:

Fully Qualified Domain Name (FQDN)

The FQDN includes the host name and all domain names separated by periods. The final period (which is for the root domain) is often omitted and only implied.

IGMP

The Internet Group Management Protocol (IGMP) is used to identify group members and to forward multicast packets on to the segments where group members reside.

Anycast

The anycast address is a unicast address that is assigned to more than one interface, typically belonging to different hosts. An anycast packet is routed to the nearest interface having that address (based on routing protocol decisions). Details include the following: > An anycast address is the same as a unicast address. Assigning the same unicast address to more than one interface makes it an anycast address. > You can have a link-local, unique local, or global unicast anycast address. > When you assign an anycast address to an interface, you must explicitly identify the address as an anycast address to distinguish it from a unicast address. > Anycast addresses can be used to locate the nearest server of a specific type (for example, the nearest DNS or network time server).

DHCP Request (R)

The client accepts the offered IP address by sending a DHCP request back to the DHCP server.

DHCP Request (R)

The client accepts the offered address by sending a DHCP request back to the DHCP server. If multiple offers were sent, the DHCP request message from the client also informs the other DHCP servers that their offers were not accepted and the IP addresses contained in their offers can be made available to other clients.

Static Full Assignment

The entire 128-bit address and all other configuration information is statically assigned to the host.

Troubleshoot DNS Name Resolution With Commands

The following table lists several ways to troubleshoot with commands:

tracert or traceroute

The tracert or traceroute commands are used to show details about the path that a packet takes from the computer to whatever destination you specify.

5.6.4 IPv4 to IPv6 Migration

The worldwide transition from IPv4 to IPv6 will be a long process. Although IPv6 is not yet widely adopted, you can implement it if your systems support it. As the implementation of IPv6 proceeds, there will be times when compatibility with IPv4 will be necessary.

5.8.5 Explore IP Configuration

You are a network technician for a small corporate network. The network is connected to the internet and uses DHCP for address assignment. Employees in Office 1 and the Executive Office are reporting problems with their network connections. In this lab, your task is to explore, diagnose, and fix the reported TCP/IP configuration problems. Complete this lab as follows: 1. On CorpServer in the Networking Closet computer, mouse over the Network icon in the notification area. - On CorpServer, the Network icon in the notification area appears normal, which indicates a connection to the local network and to internet. When you mouse over the Network icon, you see the details of this status. 2. In the notification area, right-click the Network icon and select Open the Network and Sharing Center. - The Network and Sharing Center diagram confirms that CorpServer is connected to the local network and the internet. 3. Ping CorpServer (local workstation) and the ISP to verify connectivity to the internet as follows: a. Right-click Start and select Command Prompt (Admin) to open a command window.The ping to CorpServer (local workstation) and the ISP succeed, verifying a valid connection to the internet. b. At the command prompt, enter ipconfig /all to check the Ethernet configuration.Using ipconfig /all provides the following information about the vEthernet (External) on CorpServer: - DHCP Enabled: No. This tells us that the server is configured with a static IP address and is not enabled for DHCP - IPv4 Address: 192.168.0.10 - Subnet Mask: 255.255.255.0. The server is using the default subnet mask for the Class C IP address range. - Default Gateway: 192.168.0.5. The router's internal interface is configured as the default gateway. c. At the command prompt, enter tracert to see the path to the ISP. - Using tracert 65.86.1.1 verifies a path to the ISP through our default gateway. 4. In the Executive Office, check the status of the link and network activity lights as follows: a. From the navigation tabs at the top, select Floor 1 Overview. b. Under Executive Office, select Hardware. c. Above the workstation, select Back to switch to the back view of the workstation. - The link and network activity lights on the back of the workstation are on and blinking, indicating that there is a physical connection to the switch and there is activity on the connection. This points to a TCP/IP configuration problem. 5. Verify the connectivity on the Exec workstation as follows: a. On the Exec monitor, select Click to view Windows 10. b. In the notification area, mouse over the Network icon. c. Right-click the Network icon and select Open the Network and Sharing Center. - On the Exec workstation, the network icon in the notification area has a yellow warning sign with an exclamation point, which indicates a connection to the local network, but no access to the internet. When you select the Network icon, you see the details of this status. The Network and Sharing Center diagram confirms that Exec is connected to the local network, but has no internet access. 6. On Exec, you are able to ping the local interface on Exec by name (since you don't know the IP address yet), but you can't ping CorpServer or the ISP. This indicates that Exec has a valid connection, but can't communicate with CorpServer or the ISP. 7. Using ipconfig /all provides the following information about the Ethernet connection on Exec: - DHCP Enabled: No - IPv4 Address: 192.168.0.62 - Subnet Mask: 255.255.255.240 - Default Gateway: 192.168.0.4 This information provides us with at least two clues to the problem: 1. The network is using DHCP, but this workstation is not enabled for DHCP. 2. Given the workstation's current subnet mask, the IPv4 Address of the workstation and the default gateway are not on the same network. In addition, the subnet mask is not the default subnet mask for the Class C IP address range being used. With 255.255.255.240 as a subnet mask, the network would only include addresses from 192.168.0.48 to 192.168.0.63. The IP address for CorpServer (192.168.0.10) and the ISP fall outside of this range. The information in step 3 confirms that the default subnet mask for the Class C IP address range (255.255.255.0) is being used. 8. After correcting the subnet mask on Exec, there are still no changes to the network icon or the diagram in the Network and Sharing Center. 9. After correcting the subnet mask on Exec, you can now ping CorpServer, but you still can't ping the ISP. This indicates that you only have local connectivity. 10. Use tracert 65.86.1.1. The command times out, indicating the following: - The ICMP packets are not returning from the first hop (gateway) in its path to the ISP. Exec is not finding the gateway. - The gateway address on Exec is not configured correctly. (The gateway address (router) on the network diagram is 192.168.0.5.) 11. After configuring the correct gateway address on Exec, the network icon and the diagram in the Network and Sharing Center confirm that Exec is connected to the internet. 12. Using the tracert command again returns a path to the ISP through the gateway. Since we have a valid connection to the internet, we will leave the static address for now while we troubleshoot in Office 1. 13. In Office 1, the link and network activity lights on the back of the workstation are on and blinking. Once again, this points to a TCP/IP configuration problem. 14. On Office1, the network icon and the diagram in the Network and Sharing Center indicate that Office1 is connected to the unidentified network and has no internet access. 15. You are able to ping the local interface, but you can't ping CorpServer or the ISP. This indicates that Office1 has a valid connection to the local network. 16. Using ipconfig /all provides the following information about the Ethernet connection: - DHCP Enabled: Yes. This tells us that the workstation is configured to use a DHCP server. - IPv4 Address: This address is in the APIPA range (169.254.0.1 to 169.254.255.254). This means that the workstation assigned itself an IP address instead of receiving one from the DHCP server. The workstation will only be able to communicate with other hosts on the local network that have also configured their own IP address through APIPA. - Subnet Mask: 255.255.0.0. This is the default subnet mask for the APIPA address. - Default Gateway: The address is blank. This means that communication is limited only to other workstations on the local network. - DHCP Server line is not shown. This means that the workstation was unable to contact the DHCP server. - DNS Servers line is not shown for IPv4. - Since DHCP is enabled, the rest of the information should have come from the DHCP server. We can conclude that there is an issue with the DHCP server. 17. On CorpDHCP, launch the DHCP console and activate the scope. 18. On Office1, the ipconfig /renew command will request new IP address information from the DHCP server, and it will reconfigure the settings for the Ethernet connection. 19. The ipconfig /all command will check the Ethernet configuration. You should notice the line for the default gateway, DNS server, and DHCP server, along with the new IP address, which is now within the DHCP scope for the local network. 20. After activating the DHCP server and receiving a valid IP Address, you can now ping CorpServer from Office1, but you still can't ping the ISP. 21. The tracert command times out on Office1, indicating that it can't get to the gateway. As noted above, the gateway should be 192.168.0.5. 22. The ipconfig /all command shows the default gateway is set to 192.168.0.2, but we know it should be 192.168.0.5. Since this address is coming from DHCP, we need to check the DHCP server. 23. On CorpDHCP, launch the DHCP console and reconfigure the settings for the DHCP scope. 24. On Office1, the ipconfig /renew command will request new IP address information from the DHCP server, and it will reconfigure the settings for the Ethernet connection. 25. Use the ipconfig /all command to check the Ethernet configuration. You should notice that the line for the default gateway is now configured correctly. 26. The network icon and the diagram in the Network and Sharing Center indicate that Office1 is connected to the local network and the internet. 27. When you ping the ISP to confirm resolution, the ping succeeds. 28. On Exec, reconfigure the Ethernet connection to use DHCP. 29. The ipconfig /all command now shows the IP address, default gateway, DNS server, and DHCP server that were provided by the DHCP server. 30. The network icon and the diagram in the Network and Sharing Center indicate that Exec is connected to the corporate network with full internet access. 31. Use tracert 65.86.1.1, which returns a path to the ISP through the gateway. The network is now fully functional, and your troubleshooting is complete.

Which TCP/IP utility gives you the following output?

arp -a The arp -a command shows the current entries in the computer's ARP cache.

arp

arp -a shows the IP address-to-MAC address mapping table (the address cache).

arp table

arp tables allow a system to build frames targeting remote MAC addresses.

5.6.8 IPv6 Address Assignment Facts

You can configure an IPv6 address with any of the methods in the following table.

5.4.3 Configure a DHCP Relay Agent

You just installed the DHCP service on the CorpDHCP server. You configured two scopes. The scope for Building A, Subnet1, is configured on 192.168.0. The scope for Building B, Subnet2, is configured on 192.168.10. After activating the scopes, you find that clients on Subnet1 receive IP addressing information from the DHCP server, but clients on Subnet2 have IP addresses in the 169.254.0.0/16 range. You realize that DHCP messages are not being forwarded through the router. In this lab, your task is to complete the following: > Use Routing and Remote Access to configure CorpServer2 as a DHCP relay agent by performing the following: - Add the DHCP relay agent routing protocol. - Add NetTeam as a DHCP relay agent interface. - Set the boot threshold to 0. - Configure the DHCP relay agent properties to identify 192.168.0.14 as the DHCP server. > Renew the TCP/IP information on Exec2 (the client machine in Building B). > Verify that Exec2 has a network connection. Complete this lab as follows: 1. Add the DHCP relay agent routing protocol as follows: a. In Server Manager, select Tools > Routing and Remote Access. b. Expand IPv4. c. Right-click General and select New Routing Protocol. d. Select DHCP Relay Agent; then click OK. 2. Add and configure a relay agent interface as follows: a. In the left pane, right-click DHCP Relay Agent and select New Interface. b. Select NetTeam; then click OK. c. Make sure Relay DHCP packets is selected. d. Set the boot threshold. e. Click OK. 3. Configure the DHCP relay agent properties to identify the DHCP server as follows: a. Right-click DHCP Relay Agent and select Properties. b. In the Server address field, enter the IP address of the DHCP server. c. Select Add; then click OK. 4. Renew the TCP/IP address and verify the connection as follows: a. From the top menu, select Floor 1. b. Select Exec2. c. Right-click Start and select Command Prompt (Admin). d. In the command prompt, type ipconfig /renew and press Enter. The computer should receive an address on the 192.168.10 network. e. From the the taskbar, select the Network icon to view the connection status.

Incorrectly Configured DHCP Server

Your DHCP server can send out various IP configuration values, like the IP address and mask. If network hosts are configured with incorrect IP values (such as incorrect default gateway or DNS server addresses), first verify that the workstations are contacting the correct DHCP server. If the correct server is being used, go to the DHCP server to verify that it is sending out correct configuration information.

ipconfig

ipconfig is a command line tool used to control the network connections on Windows machines.

You have a network with 50 workstations. You want to automatically configure workstations with the IP address, subnet mask, and default gateway values. Which device should you use?

DHCP server Use a DHCP server to deliver configuration information to hosts automatically. Using DHCP is easier than configuring each host manually. Use a gateway to provide access to a different network or a network that uses a different protocol. Use a router to connect multiple subnets. Use a DNS server to provide name resolution (for example, to get the IP address associated with a logical host name).

Local Host

Addresses in the 127.0.0.0 range are reserved to refer to the local host (the host you're currently working at). The most commonly used address is 127.0.0.1, which is the loopback address.

ANDing

The process used to determine the network address/ID.

DHCP Offer (O)

A DHCP server that receives a Discover request from a client responds with a DHCP Offer advertisement, which contains an available IP address. If more than one DHCP server responds with an offer, the client usually responds to the first offer it receives.

Classless Inter-Domain Routing (CIDR)

A set of internet protocol standards used to create unique identifiers for networks and host devices.

Custom Example

Network Address - 188.50.0.0 Subnet Mask - 255.255.255.0 # of Subnet Addresses - 254 # of Hosts per Subnet - 254 per subnet Subnet Address(es) - 188.50.1.0, 188.50.2.0, 188.50.3.0, (and so on) Host Address Range(s) - 188.50.1.1 to 188.50.1.254 188.50.2.1 to 188.50.2.254 188.50.3.1 to 188.50.3.254 (and so on)

5.3.9 DHCP Configuration Facts

The dynamic host configuration protocol (DHCP) centralizes management of IP addressing in a network by allowing a server to dynamically assign IP addresses to clients. DHCP also allows mobile users, who move from network to network, to easily obtain an IP address appropriate for each network they connect to.

5.1.9 IP Address Assignment Facts

The following table lists several options for assigning IP addresses.

VLSM

Variable Length Subnet Masking (VLSM) is the method used to divide an IP address into subnets of different sizes. When using VLSM, you ignore the default subnet mask boundaries and specify a custom number of subnet mask bits.

Alternate IP Configuration

With an alternate IP configuration, static IP configuration values are used if a DHCP server cannot be contacted. When you configure an alternate IP address, APIPA is automatically disabled. It is recommended that you use an IP configuration other than APIPA because you hosts need to access other systems on the local subnet and on other networks, including the internet. Alternate IP configuration also allows continued access to servers and other network infrastructure devices that use static IP addresses.

Which of the following is the last IP address that can be assigned to hosts on the 166.70.0.0 network using the default subnet mask?

166.70.255.254 The last address you can assign to hosts on the 166.70.0.0 network is 166.70.255.254. The network address is a Class B address and uses a default subnet mask of 255.255.0.0. The last two octets are used for host addresses. 166.70.0.0 cannot be used as a host address because it is the network address. 166.70.255.255 cannot be used as a host address because it is the broadcast address.

Which of the following IP address ranges is reserved for automatic private IP addressing?

169.254.0.1 - 169.254.255.254 The Internet Assigned Numbers Authority (IANA) has reserved 169.254.0.1 through 169.254.255.254 for automatic private IP addressing (APIPA). APIPA also sets the subnet mask on the network to 255.255.0.0.

You've decided to use a subnet mask of 255.255.192.0 on the 172.17.0.0 network to create four separate subnets. Which network IDs will be assigned to these subnets in this configuration? (Select two.)

172.17.128.0 172.17.0.0 The subnet mask used for the 172.17.0.0 network can be viewed in binary notation as 11111111.11111111.11000000.000000. Because the first two bits of the third octet are used for the network portion of the address, four subnets are possible: 172.17.0.0 172.17.64.0 172.17.128.0 172.17.192.0

Your network has been assigned the Class B network address of 179.113.0.0. Which three of the following addresses can be assigned to hosts on your network?

179.113.65.12 179.113.89.0 179.113.0.118 All hosts on this network must share the first two octets of the IP address (179.113). You cannot assign 179.113.0.0 to a host because this address indicates the address of the network.

Consider the following output from a dig command run on a Linux system. ; <<>> DiG 8.2 <<>> westsim111.com ;;res options:init recurs defnam dnsrch ;;got answer: ;;->>HEADER<<-opcode:QUERY, status: NOERROR, id:4 ;;flags: qr rd ra; QUERY:1, ANSWER:1, AUTHORITY:2, ADDITIONAL:0 ;;QUERY SECTION: ;; westsim111.com, type = A, class = IN ;;ANSWER SECTION: westsim111.com. 7h33m IN A 76.141.43.129 ;;AUTHORITY SECTION: westsim111.com. 7h33m IN NS dns1.deriatct111.com. westsim111.com. 7h33m IN NS dns2.deriatct222.com. ;;Total query time: 78 msec ;;FROM: localhost.localdomain to SERVER:default -- 202.64.49.150 ;;WHEN: Tue Feb 16 23:21:24 2005 ;;MSG SIZE sent: 30 rcvd:103 What is the IP address of the DNS server that performed this name resolution?

202.64.49.150 When the dig command is used to perform a manual DNS lookup, a range of information is provided. The IP address of the DNS server that performed the name resolution is shown in the bottom area of the output, on the end of the ;;FROM line. The IP address shown in the answer section denotes the resolved IP address for the domain or host for which the resolution was requested. In this case, that address is 76.141.43.129. The other two answers are invalid.

What is the network address and subnet mask used by APIPA? (Select two.)

255.255.0.0 169.254.0.0 Automatic private IP addressing (APIPA) uses a network address of 169.254.0.0 with the default Class B subnet mask of 255.255.0.0. Host addresses are within the range of 169.254.0.1 and 169.254.255.254.

4-to-6 Tunneling

4-to-6 tunneling works in a manner similar to 6-to-4 tunneling. However, instead of tunneling IPv6 traffic through an IPv4 network, 4-to-6 tunnels IPv4 traffic through an IPv6 network by encapsulating IPv4 packets within IPv6 packets.

Which of the following tunneling methods is used to send IPv4 traffic through an IPv6 network?

4to6 tunneling 4to6 tunneling is used to send IPv4 traffic through an IPv6 network by encapsulating IPv4 packets within IPv6 packets. 6to4 tunneling is used to send IPv6 traffic through an IPv4 network. ISATAP is used to provide IPv6 communication over a private IPv4 network. Toredo tunneling establishes a tunnel between individual IPv6 hosts so they can communicate through a private or public IPv4 network.

You manage a network with two locations, Portland and Seattle. Both locations are connected to the internet. All computers in both locations are configured to use IPv6. You would like to implement an IPv6 solution to meet the following requirements: > Hosts in each location should be able to use IPv6 to communicate with hosts in the other location through the IPv4 internet. > You want to use a site-to-site tunneling method instead of a host-to-host tunneling method. Which IPv6 solution should you use?

6to4 Use 6to4 tunneling to create a router-to-router tunnel between two sites through an IPv4 network. Use the intra-site automatic tunnel addressing protocol (ISATAP) to enable IPv6 hosts to communicate over a private IPv4 network within a site; ISATAP does not work between sites. Use Teredo on two hosts separated by symmetric NAT to configure host-to-host tunneling. Use 4to6 tunneling to allow IPv4 traffic on an IPv6 network.

The DHCP console provides context-sensitive icons to reflect DHCP server status as follows:

> A check mark in a green circle indicates that the DHCP server is connected and authorized. > A red down arrow indicates that the DHCP server is connected, but not authorized. > A horizontal white line inside a red circle indicates that the DHCP server is connected, but the current user does not have the administrative credentials necessary to manage the server. > An exclamation point inside a yellow triangle indicates that 90% of available addresses for server scopes are either in use or leased. > An exclamation point inside a blue circle indicates that 100% of available addresses for server scopes are either in use or leased.

Remember that the last valid host address ends with 254 because 255 is a broadcast address and is not available as a host address. For example:

> For the class A network address 115.0.0.0, the host range is 115.0.0.1 to 115.255.255.254. > For the class B network address 154.90.0.0, the host range is 154.90.0.1 to 154.90.255.254. > For the class C network address 221.65.244.0, the host range is 221.65.244.1 to 221.65.244.254. *While subnetting divides a large address space into multiple subnets, supernetting combines multiple small network addresses into a single larger network. Supernetting allows multiple Class C addresses to be combined into a single network.

Because IP addresses assigned to hosts must be unique, the use of IP addresses on the internet is controlled by organizations that ensure that every organization is given its own range of IP addresses to assign to hosts:

> The Internet Assigned Numbers Authority (IANA) manages the assignment of IP addresses on the internet. IANA is operated by the Internet Corporation for Assigned Names and Numbers (ICANN). > IANA allocates blocks of IP addresses to Regional Internet Registries (RIRs). An RIR has authority over IP addresses in a specific region of the world. > An RIR assigns blocks of addresses to Internet Service Providers (ISPs). > An ISP assigns one or more IP addresses to individual computers or organizations connected to the Internet.

When configuring IP addresses, keep in mind the following:

> You cannot assign the subnet address to a host (such as 192.168.0.0 or 10.0.0.0). > The /x notation identifies the number of bits in the subnet mask. - /8 indicates a subnet mask of 255.0.0.0. - /16 indicates a subnet mask of 255.255.0.0. - /24 indicates a subnet mask of 255.255.255.0. > Portions of the subnet mask that include a 1 identify the subnet address. This portion of the address must be the same for all hosts on the subnet. > Portions of the subnet mask that include a 0 identify the host address. This portion of the address must be unique between all hosts. > You cannot assign the last address to a host (such as 192.168.0.255 or 10.0.255.255).

Subnet Mask

A 32-bit number that defines which portion of an IPv4 address identifies the network address and which portion of the address defines the host address.

Network ID

A 32-bit number that identifies the network an IPv4 address belongs to.

Dynamic Host Configuration Protocol (DHCP)

A DHCP server is a special server configured to pass out IP addresses and other IP configuration information to network clients. DHCP servers ensure that each client is assigned a unique IP address. > When a DHCP client system boots, it contacts the DHCP server for IP configuration information. The DHCP server is configured with a range of IP addresses it can assign to hosts. These ranges are called scopes. - The DHCP server can be configured to prevent specific addresses in the range from being assigned to clients. This is called an exclusion. - You can also configure a DHCP server to deliver the same address to a specific host each time it requests an address. This is called a reservation. > The DHCP server can also be configured to pass out other IP configuration information, such as the default gateway and DNS server addresses. > The DHCP server assigns the IP address and other information to the client. The assignment is called a lease, and it includes a lease time that identifies how long the client can use the IP address. - Periodically, the client contacts the DHCP server to renew the lease on the IP address. The client will also attempt to renew the lease on the same IP address if it reboots. - The DHCP lease process uses broadcast frames at Layer 2. For this reason, DHCP requests do not pass through routers to other subnets by default. To enable DHCP broadcasts between subnets, enable IP helper or DHCP relay on the appropriate routers. - When the lease expires, the DHCP server releases the reserved IP address. This is known as the expired IP address. > Any client configured to use DHCP can get an IP address from any server configured for DHCP, regardless of its operating system. *DHCP is the preferred IP configuration method for small, medium, and large networks.

DHCP Offer (O)

A DHCP server that receives a Discover request from a client responds with a DHCP Offer advertisement, which contains an available IP address. If more than one DHCP server responds with an offer, the client usually responds to the first offer that it receives.

Dual Stack

A dual stack configuration enables a host to communicate with IPv4 and IPv6 hosts; the IPv4 and IPv6 protocol stacks run concurrently on a host.

Dual Stack

A dual stack configuration enables a host to communicate with IPv4 and IPv6 hosts; the IPv4 and IPv6 protocol stacks run concurrently on a host. IPv4 is used to communicate with IPv4 hosts, and IPv6 is used to communicate with IPv6 hosts. When dual stack is implemented on hosts, intermediate routers and switches must also run both protocol stacks.

DHCP Relay Agent

A function of the Routing and Remote Access service (RRAS) role on a Windows server, the DHCP Relay Agent service sends the DHCP packets it receives to a remote DHCP server on a different subnet.

IPv6 Address Management

A good way to manage IP addresses is to use IP address management (IPAM). IPAM allows you to plan, track, and manage IP addresses using integrated DHCP and DNS information. This allows administrators to keep a pool of assignable IP addresses up-to-date. IPAM tools are becoming more important for managing IPv6 networks because IPv6 networks have larger address pools, different subnetting techniques, and more complex 128-bit hexadecimal numbers. IPAM can manage the following information: > IP addresses in use > The user an IP address is assigned to > Free IP address space > The size of subnets, who uses them, and how many subnets are in use > IP address status (permanent vs. temporary) > Default routers that the various network devices use > The host name associated with each IP address > The hardware associated with each IP address

Alternate IP Configuration

A manual configuration of a computer's IP address, default gateway, DNS server address, and WINS address. This configuration is used if the DHCP server fails to provide this similar information.

Rogue DHCP Server

A rogue DHCP server is an unauthorized DHCP server on the network. Symptoms of a rogue DHCP server include: > Conflicting IP addresses on the network > Duplicate IP addresses on the network > Incorrect IP configuration information on some hosts To identify a rogue DHCP server using ipconfig, verify the DHCP server address. If this address is not the address of your DHCP server, you have a rogue DHCP server. *When you have a rogue DHCP server on the network, some hosts will likely receive configuration information from the correct DHCP server and others from the rogue DHCP server.

Broadcast

A single packet is sent to the broadcast address and is processed by all hosts. All hosts, and not just group members, receive the packet. Broadcast packets are not typically forwarded by routers, so broadcast traffic is limited to within a single subnet.

Broadcast

A single packet that, when sent, is processed by all hosts. Broadcast packets are not typically forwarded by routers, so broadcast traffic is limited to within a single subnet.

Anycast

A unicast address that is assigned to more than one interface, typically interfaces belonging to different hosts.

Automatic Private IP Addressing (APIPA)

APIPA provides an option for automatic IP address assignment without a DHCP server. APIPA is enabled by default on most modern operating systems, including Windows and Linux. Using APIPA, hosts can assign themselves an IP address on the 169.254.0.0 network (with a mask of 255.255.0.0) if they can't locate a DHCP server. If a network host is configured to use dynamic IP addressing and a DHCP server can't be contacted, APIPA assigns a temporary IP address to the host. However, only the IP address and mask are assigned. Default gateway and DNS server addresses are not assigned. For this reason, APIPA can be used only to enable communications within a single subnet. Communication with other networks, including the internet, are not possible. In addition, communication with network infrastructure devices that use static IP addressing, such as servers, is not possible even if they are on the same local subnet as the APIPA host.

Additional Domains

Additional domains are second-level domains with names registered to an individual or organization for use on the internet. These names are based on an appropriate top-level domains, depending on the type of organization or geographic location where a name is used. Yahoo.com and microsoft.com are examples of additional domains in your DNS structure.

Additional Facts

Additional multicasting facts include: > Frames that contain multicast traffic are sent to a special MAC address. The MAC address begins with 01-00-5E, with the last portion being a form of the IP multicast group address. A single multicast MAC address could be shared by up to 5 other IP multicast addresses. > A regular switch that receives multicast traffic sends the traffic out all ports, because the destination MAC address will be an unknown address. This means that a host might see multicast traffic on its segment, even if it isn't a member of the group. However, hosts that are not members of the group will not process the frame because they will not associate the multicast MAC address with their own address. > IGMP snooping on a switch allows the switch to control which ports get IGMP traffic for a specific group. With IGMP snooping, the switch identifies which ports include members of a specific multicast group. When a message is received for a group, the message is sent only to the ports that have a group member connected.

B Class

Address Range - 128.0.0.0 to 191.255.255.255 First Octet Range - 128-191 (10000000-10111111 binary) Default Subnet Mask - 255.255.0.0

C Class

Address Range - 192.0.0.0 to 223.255.255.255 First Octet Range - 192-223 (11000000-11011111 binary) Default Subnet Mask - 255.255.255.0

D Class

Address Range - 224.0.0.0 to 239.255.255.255 First Octet Range - 224-239 (11100000-11101111 binary) Default Subnet Mask - n/a

E Class

Address Range - 240.0.0.0 to 255.255.255.255 First Octet Range - 240-255 (11110000-11111111 binary) Default Subnet Mask - n/a

Unique-Local

An IPv6 address type that indicates an IP address is a private IP address.

Multicast

An IPv6 address type that indicates that the packet is addressed to a number of hosts on the network, but not all hosts.

Global-Unicast

An IPv6 address type that is publicly routable and can be used in the internet.

RFC 1542 Compliant Router

An RFC 1542 compliant router listens for DHCP traffic and routes any received DHCP frames to the appropriate subnet. .

RFC 1542 Compliant Router

An RFC 1542 compliant router listens for DHCP traffic and routes any received DHCP frames to the appropriate subnet. For example, on a Cisco router, you can enable this functionality by using the ip helper-address command. The syntax is: ip helper-address [server_address] Replace [server_address] with the IP address of the remote DHCP server.

Authoritative Server

An authoritative server is a DNS server that has a complete copy of all the records for a particular domain.

You administer a network with Windows Server 2016 and UNIX servers and Windows 10 Professional, Windows 7, and Macintosh clients. A Windows 7 computer user calls you one day and says he is unable to access resources on the network. You type ipconfig on the user's computer and receive the following output: 0 Ethernet adapter: IP address: 169.254.1.17 Subnet Mask: 255.255.0.0 Default Gateway: You also check your NIC and see the link light on. What might the problem be?

An unavailable DHCP server. If a Windows 7 client computer is configured to use DHCP and cannot locate one to receive IP addressing information, it assigns itself an IP address from the APIPA (Automatic Private IP Addressing) range of IP addresses. APIPA addresses include IP addresses from 169.254.0.0 to 169.254.255.254 and are reserved for this purpose. A lit link light on your NIC indicates a connection to the network.

5.9.3 Network Communication Troubleshooting Facts

As part of the troubleshooting process, you need to identify the scope of the problem so you can take the proper actions to correct the problem. In this scenario, Workstation A can't communicate with Workstation C.

Special Considerations

As you are assigning IP addresses to hosts, think of the following special considerations:

5.7 Multicast

As you study this section, answer the following questions: > How does multicast differ from unicast and broadcast? > What is the IP address range reserved for multicast groups? > What does a regular switch do when it receives a multicast frame? > Which device would you configure to prevent multicast traffic from being sent to non-group members? The key terms for this section include:

5.10 Troubleshoot Name Resolution

As you study this section, answer the following questions: > What are the symptoms of name resolution problems? > What is the difference between nslookup and dig? In this section, you will learn to: > Use nslookup The key terms for this section include:

5.8 Troubleshoot IP Configuration Issues

As you study this section, answer the following questions: > What does the /release switch do when used with ipconfig? > How can you tell if a rogue DHCP server is active on your network? > How do you know if a host is using APIPA? In this section, you will learn to: > Find information about IP configuration settings on Windows and Linux systems. > Troubleshoot IP configuration problems. The key terms for this section include:

5.1 IP Addressing

As you study this section, answer the following questions: > What is an octet? > What is the decimal equivalent of the following binary number? 01100111. What is the binary equivalent of the following decimal number? 211. > How is the network portion of an IP address identified? > Which portion of a class C address designates the network address? > What is the difference between subnetting and supernetting? Which method uses a subnet mask that is longer than the default subnet mask? > What does /14 mean in the following IP address: 199.78.11.12/14? > How does variable-length subnet masking work? In this section, you will learn to: > Configure IP addresses. > Configure IP addresses on mobile devices.

5.9 Troubleshoot IP Communications

As you study this section, answer the following questions: > What is the difference between netstat and arp? > If a ping test fails, what should you do? > What information does tracert provide? > What does TCPdump do? In this section, you will learn to: > Use ping and tracert. > Use arp and netstat. > Use tcpdump. > Explore network communications. The key terms for this section include:

5.6 IP Version 6

As you study this section, answer the following questions: > What is the primary reason for developing IPv6? > How many hexadecimal numbers are in an IPv6 address? How does this compare to a MAC address? > What do you add to an IPv6 address when you remove one or more quartets with all 0s? > What information is included within the IPv6 address prefix? > How many numbers are used for the interface ID? How can the interface ID be related to the MAC address? > What is the difference between ISATAP and 6to4 tunneling? > What is the difference between stateful autoconfiguration and stateless autoconfiguration? In this section, you will learn to: > Configure IPv6 addresses. > Configure a DHCP6 server. > Configure an IPv6 address. The key terms for this section include:

5.5 DNS Name Resolution

As you study this section, answer the following questions: How are host names organized in DNS? What is the difference between a forward lookup zone and a reverse lookup? What is the role of the root servers in DNS? In DNS, what is the difference between a zone and a domain? What is the difference between an A record and a PTR record? In this section, you will learn to: Configure DNS addresses. Create standard DNS zones. Create reverse DNS zones. Create host records. Create CNAME records. Troubleshoot DNS records.

5.2 APIPA and Alternate Addressing

As you study this section, answer the following questions: How do you know if a host is using an APIPA address? Which IP configuration parameters are set when APIPA is used? Which parameters are not set? In which scenarios would an alternate IP configuration simplify IP configuration? In this section, you will learn to: Set Up alternate addressing. Configure alternate addressing.

5.4 DHCP Relay

As you study this section, answer the following questions: What is the difference between an RFC 1542 compliant router and a DHCP relay agent? In this section, you will learn to: Configure a DHCP relay agent Add a DHCP server on another subnet

5.3 DHCP Server Configuration

As you study this section, answer the following questions: What type of configuration parameters can be delivered using DHCP? What are the advantages of static IP address assignments? When might you want to use static IP addressing? In this section, you will learn to: Configure a DHCP server. Configure DHCP options. Create DHCP exclusions. Create DHCP client reservations. Configure a DHCP client.

5.5.9 Practice Questions

CIST 1401

5.6.10 Practice Questions

CIST 1401

5.7.3 Practice Questions

CIST 1401

5.8.9 Practice Questions

CIST 1401

5.9.9 Practice Questions

CIST 1401

tcpdump -n dst net 192.168.0.0/24

Capture any packets that list 192.168.0.0/24 as the destination network. Displays IP addresses and port numbers.

tcpdump -n "dst host 192.168.1.1 and (dst port 80 or dst port 443)"

Capture any packets that list 192.168.0.1 as the destination IP and 80 or 443as the destination port. Displays IP addresses and port numbers.

tcpdump -n host 192.168.0.1

Capture any packets that list 192.168.0.1 as the source or destination host. Displays IP addresses and port numbers.

tcpdump -n src net 192.168.1.0/24

Capture any packets that list 192.168.1.0/24 as the source network. Displays IP addresses and port numbers.

tcpdump -n dst port 23

Capture any packets that list 23 as the destination port. Displays IP addresses and port numbers.

Classful IP Addresses

Classful addresses are IP addresses that use a default subnet mask, as follows: Class A: 255.0.0.0 Class B: 255.255.0.0 Class C: 255.255.255.0 They are considered classful because the default subnet mask identifies the network portion and host portion of the IP address.

You manage a server that uses an IP address of 192.168.255.188 with a mask of 255.255.0.0. Which of the following describes the address type?

Classless Because the IP address is not using the default subnet mask, it is using classless addressing. Classless addressing modifies the length of the subnet mask, using a custom mask value instead of the default subnet mask. Classful addressing uses the default subnet mask. Devices that only support classful addressing assume the subnet mask based on the IP address class. A broadcast address is an address that is sent to all hosts. Broadcast addresses are the last possible address on a subnet. A multicast address is an address that identifies a group of computers. Members of the group share the same multicast address. Multicast addresses are in the range of 224.0.0.0 to 239.255.255.255. A public address is an address that is registered for use on the internet.

Classless IP Addresses

Classless addresses, on the other hand, use a custom mask value to separate the network and host portions of the IP address. Classless addressing is made possible using Classless Inter-Domain Routing (CIDR). CIDR allows you to use only part of an octet for the network address. This is called partial subnetting, or variable-length subnet masking (VLSM).

Stateless Autoconfiguration

Clients automatically generate the interface ID and learn the subnet prefix and default gateway through the Neighbor Discovery Protocol (NDP).

Stateless Autoconfiguration

Clients automatically generate the interface ID and learn the subnet prefix and default gateway through the Neighbor Discovery Protocol (NDP). NDP uses the following messages for autoconfiguration: > A Router solicitation (RS) is a message the client sends to request router response. > A Router advertisement (RA) is a message the router sends at two times: in response to RS messages and to inform clients of the IPv6 subnet prefix and default gateway address. Hosts also use NDP to discover the addresses of other interfaces on the network, removing the need for the Address Resolution Protocol (ARP). *NDP provides enough information for to address the client and for clients to learn the addresses of other clients on the network. However, it does not provide the client with DNS server information or any other IP configuration information besides the IP address and the default gateway.

5.10.2 Name Resolution Troubleshooting Facts

Common name resolution problems include the following: > The DNS server could be down or otherwise unreachable. > There may be a routing problem between the sending host and the DNS server. > The sending host could be configured with the wrong IP address for the DNS server. Name resolution problems typically have the following symptoms: > You can ping a destination host using its IP address, but not its host name. > Applications that use hostnames fail. This could include: - Entering a URL into a browser. - Pinging the host using the hostname. - Searching for the host by its name. To troubleshoot DNS name resolution, use the following tools: > ping > tracert (Windows) or traceroute (Linux) > nslookup > dig (Linux) > host (Linux)

-t

Create a timestamp output humans can read.

-tttt

Create a timestamp output that's maximally readable for humans.

Dynamic DNS (DDNS)

DDNS enables clients or the DHCP server to update records in the zone database. Without dynamic updates, all A (host) and PTR (pointer) records must be configured manually. With dynamic updates, host records are created and deleted automatically whenever the DHCP server creates or releases an IP address lease. Dynamic updates occur when: > A network host's IP address is added, released, or changed. > The DHCP server changes or renews an IP address lease. > The client's DNS information is manually changed using ipconfig /registerdns.

You have a TCP/IP network with 50 hosts. There have been inconsistent communication problems between hosts. You run a protocol analyzer and discover that two hosts have the same IP address assigned. Which protocol can you implement on your network to help prevent problems such as this?

DHCP You can use the dynamic host configuration protocol (DHCP) to set up a DHCP server that will assign IP addresses automatically to network hosts. DHCP servers will not assign the same IP address to two different hosts.

You want to implement a protocol on your network that allows computers to find the IP address of a host from a logical name. Which protocol should you implement?

DNS DNS is a system that is distributed throughout the internetwork to provide address/name resolution. For example, the name www.mydomain.com would be identified with a specific IP address. ARP is a protocol for finding the IP address from a known MAC address. DHCP is a protocol used to assign IP addresses to hosts. Telnet is a remote management utility.

You need to enable hosts on your network to find the IP address of logical names such as srv1.myserver.com. Which device would you use?

DNS server Use a DNS server to provide host-name-to-IP-address resolution. A bandwidth shaper modifies the flow of traffic to keep traffic within predefined limits. A load balancer accepts incoming client requests and distributes those requests to multiple other servers. An IDS detects security threats, while an IPS can both detect and respond to security threats.

You have a small network, as shown in the Exhibit. You have configured the IP address and subnet mask on Wrk1. You want to be able to use Wrk1 to browse the internet to connect to sites like www.cisco.com. Which other parameters are required on the workstation? (Select two.)

DNS server address Default gateway To access a remote network, the workstation must be configured with a default gateway address. In addition, it must be configured with one or more DNS server addresses. The DNS server address is used to contact a DNS server and find the IP address of hosts using names such as www.cisco.com. A host name is not required on the workstation to be able to contact hosts using host names on the internet. Host names are only used to identify hosts using logical names; they are not used by the device itself. If a host name is used, the computer must translate the host name (using DNS) into an IP address. A WINS server address is used for NetBIOS name resolution. This process is used on local area networks by Windows computers and is not used on the internet. A DHCP server address identifies the IP address of a DHCP server that is used to get an IP address. Most workstations automatically contact a DHCP server without having to be configured with its IP address.

-s

Define the snaplength (size) of the capture in bytes. Use -s0 to capture everything unless you are intentionally capturing less.

dig

Domain Information Groper (dig) is a Unix-like network administration command-line tool used to determine what a particular DNS server thinks the given host's IP address should be.

-nn

Don't resolve host names or port names.

-n

Don't resolve host names.

Which of the following services automatically creates and deletes host records when an IP address lease is created or released?

Dynamic DNS Dynamic DNS (DDNS) enables clients or the DHCP server to update records in the zone database automatically whenever an IP address lease is created or renewed. A forward lookup is the process of resolving a host name to an IP address. A DHCP relay is used to forward DHCP requests to a DHCP server in a different subnet. Dynamic NAT is used to automatically map internal IP addresses with a dynamic port assignment.

DHCP

Dynamic Host Configuration Protocol (DHCP) is a protocol used to centrally manage the distribution of IP addresses within a network.

Additional Facts

Exhausted DHCP scope means that all of the addresses within the DHCP scope were depleted. As a consequence, a legitimate user is denied an IP address requested through DHCP and is not able to access the network. This situation is usually caused by an attack called DHCP starvation. This attack might be a DoS mechanism or be used together with a malicious rogue server attack to redirect traffic to a malicious computer ready to intercept traffic. If the workstation has received configuration information from the wrong DHCP server or has configured itself using APIPA, you may need to contact the DHCP server again once the DHCP problems have been resolved. Use the following commands: > ipconfig /release to stop using the current dynamic IP configuration parameters. > ipconfig /renew to retry the DHCP server request process to obtain IP configuration parameters. *To display the TCP/IP configuration on a Linux computer, use the ifconfig command.

Expression Examples

Expressions allow you to filter traffic and find exactly what you need. There are three main types of expression: type, dir, and proto. > The type options are host, net (the network address), and port. > Direction lets you insert the src (source) and dst (destination) commands. > Protocol lets you designate tcp, udp, icmp, ah, and many more options. Some examples of uses for TCPdump include the following: *Commands are case sensitive.

Which of the following is a valid IPv6 address?

FEC0::AB:9007 FEC0::AB:9007 is a valid IPv6 address. The :: in the address replaces blocks of consecutive 0s. The longer form of this address is FEC0:0000:0000:0000:0000:0000:00AB:9007. Leading 0s within a quartet can also be omitted. You can only omit one block of 0s using the double colon. Each number in the IPv6 address must be between 0-9 or A-F; G is not a valid number for the IPv6 address. An address without double colons should have a total of 32 hexadecimal numbers in eight blocks.

Functions of Subnetting

From a physical standpoint, subnetting is necessary because network architectures impose a limit on the number of hosts allowed on a single network segment. As your network grows, you will need to create subnets (physical networks) to: > Increase the number of devices that can be added to the LAN (to overcome the architecture limits) > Decrease the number of devices on a single subnet (to reduce traffic congestion) > Reduce the processing load placed on computers and routers > Isolate sensitive systems on the network Subnetting is also used to efficiently allocate available IP addresses. For example, an organization with a class B network ID is allocated enough addresses for 65,536 hosts. However, if the organization in practice uses only 10,000 of those host IDs, over 55,000 IP addresses are going unused. Subnetting provides a way to break the single class B network ID into multiple smaller network IDs. > Subnetting uses custom subnet masks instead of the default subnet masks (e.g., using 255.255.255.0 with a Class B address instead of the default 255.255.0.0). > When you subnet a network by using a custom mask, you can divide the IP addresses between several subnets. However, you also reduce the number of hosts available on each network. > Using custom subnet masks is often called classless addressing because the subnet mask cannot be inferred simply from the class of a given IP address. The address class is ignored, and the mask is always supplied to identify the network and host portions of the address. The following table shows how a Class B address can be subnetted to provide additional subnet addresses. Notice that by using a custom subnet mask, the Class B address looks like a Class C address.

Global unicast

Global unicast addresses are assigned to individual interfaces that are globally unique. All IPv6 addresses that aren't specifically reserved for other purposes are defined as global unicast addresses. The global routing prefix assigned to an organization by an ISP is typically 48 bits long (/48), but it could be as short as /32 or as long as /56, depending on the ISP. All subnet IDs within the same organization must begin with the same global routing prefix, but they must also be uniquely identified using a different value in the subnet field. Using this addressing scheme allows organizations to define a large number (216) of IPv6 subnets. When you design an IPv6 network, define separate IPv6 subnets by the following: > Network segments separated by routers > VLANs > Point-to-point WAN links

Which protocol does an IP host use to inform a router that it wants to receive specific multicast frames?

IGMP IP hosts use the IGMP, or internet group management protocol, to inform multicast-enabled routers that they want to receive specific multicast frames.

You have a small network with a single subnet connected to the internet as shown in the Exhibit. The router has been assigned the two addresses shown. You need to manually configure the workstation to connect to the network. The workstation should use RouterA as the default gateway and DNS1 as the DNS server address. From the drop-down options, select the appropriate parameters to configure the workstation's TCP/IP settings.

IP Address 192.168.12.46 Subnet mask 255.255.255.240 Default gateway 192.168.12.34 DNS Server 198.162.1.22 Use the following values: > Use 192.168.12.46 for the IP address. With a 28-bit mask, the router is on subnet 192.168.12.32, and valid addresses are 192.168.12.33 to 192.168.12.46. You cannot use 192.168.12.32 because it is the subnet address. You cannot use 192.168.12.47 because it is the broadcast address. > A 28-bit mask is 255.255.255.240 in binary. > For the default gateway address, use the address assigned to the router interface that is on the same subnet as the workstation (in this example, 192.168.12.34). > For the DNS server address, use the IP address assigned to the DNS server (198.162.1.22).

You have a workstation connected to a small branch network using a single switch. The network does not have any routers and is not connected to the internet. What are the minimum configuration parameters required on the workstation to be able to communicate with all hosts on the network?

IP address and subnet mask On a single subnet, you only need to configure an IP address and a subnet mask. The default gateway identifies the router address used to reach remote networks. You would only use the default gateway if the network was connected to another subnet or the internet.

5.1.2 IP Address Facts

IP addresses allow hosts to participate on IP-based networks. The following are important things to know about IP addresses: > An IP address is a 32-bit binary number represented as four octets (four 8-bit numbers). Each octet is separated by a period. > IP addresses can be represented two different ways: - Decimal (e.g., 131.107.2.200). In decimal notation, each octet must be between 0 and 255. - Binary (e.g., 10000011.01101011.00000010.11001000). In binary notation, each octet is an 8-character number. > To convert from binary to decimal, memorize the decimal equivalent to the following binary numbers: 10000000 - 128 01000000 - 64 00100000 - 32 00010000 - 16 00001000 - 8 00000100 - 4 00000010 - 2 00000001 - 1 *Add together the decimal values of each bit position with a 1 value. For example, the decimal equivalent of 10010101 is: 128 + 16 + 4 + 1 = 149 > The IP address includes both the network and the host address. > A subnet mask is a 32-bit number associated with an IP address that identifies the network portion of the address. In binary form, the subnet mask is always a series of 1s followed by a series of 0s (1s and 0s are never mixed in sequence in the mask). A simple mask might be 255.255.255.0 (i.e., 11111111.11111111.11111111.00000000). > IP addresses have a default class. The address class identifies the range of IP addresses and the default subnet mask used for the range. The following table shows the default address class for each IP address range:

Source Intelligent Routing

IPv6 nodes have the option to include addresses that determine part or all of the route a packet will take through the network.

DHCPv6

IPv6 uses an updated version of DHCP, DHCPv6. It operates in one of two modes: > Stateful DHCPv6 is when the DHCP server provides each client an IP address, default gateway, and other IP configuration information (such as the DNS server IP address). The DHCP server tracks the status (or state) of the client. > Stateless DHCPv6 does not provide the client an IP address or track the status of each client. It supplies the client with the DNS server IP address. Stateless DHCPv6 is most useful when used in conjunction with stateless autoconfiguration.

DHCPv6

IPv6 uses an updated version of DHCP, DHCPv6. It operates in two modes, stateful and stateless.

5.6.3 IPv6 Address Type Facts

IPv6, assigns addresses to interfaces (network connections). All interfaces require an IPv6 address, and each interface can have more than one IPv6 address. IPv6 defines the following types of addresses:

5.2.4 APIPA and Alternate IP Addressing Facts

If a host is configured to obtain its IP address from a DHCP server but that server is unreachable, then an alternate IP address assignment method may be employed as follows:

Alternate Configuration

If the workstation has been configured using an alternate configuration, the following conditions will exist: > The DHCP Enabled line will show Yes. > The DHCP Server line will not be shown. > The IP address and subnet mask will be values other than the APIPA values. > Default gateway and DNS server addresses will be configured using the alternate configuration values.

DHCP Configuration

If the workstation has received configuration information from a DHCP server, the following conditions will exist: > The DHCP Enabled line will show Yes. > The DHCP Server line will show the IP address of the DHCP server that sent the configuration information.

Static IP Configuration

If the workstation is configured with static IP information, the following conditions will exist: > The DHCP Enabled line will show No. > The DHCP Server line will not be shown.

APIPA Configuration

If the workstation used APIPA to set configuration information, the following conditions will exist: > The DHCP Enabled line will show Yes. > The DHCP Server line will not be shown. > The IP address will be in the range of 169.254.0.1 to 169.254.255.254, with a mask of 255.255.0.0. > The Default Gateway line will be blank. > The DNS Servers line will not include any IPv4 addresses. When APIPA is used, the workstation sets its own IP address and mask. It does not automatically configure default gateway or DNS server values. When APIPA is being used: > Communication is restricted to hosts within the same subnet (there is no default gateway set). > Hosts can communicate with other hosts that have used APIPA. If some hosts are still using an address assigned by the DHCP server (even if the DHCP server is down), those hosts will not be able to communicate with the APIPA hosts. > Name resolution will not be performed (there are no DNS server addresses configured).

Troubleshoot the Local Host Connection or Configuration

If you cannot communicate with any host on the local network, then the problem is likely with the local host or its connection to the network. Troubleshoot by doing the following: > Check physical connectivity > Validate the TCP/IP configuration on the local host > Validate IP configuration settings

Ping Host D

If you cannot contact a specific remote host, try pinging another host in the same remote network. If the ping is successful, then the problem is with the remote host (for example, a misconfiguration, broken link, or unavailable host).

Ping Host E

If you cannot contact any host in the remote network, try pinging hosts on other remote networks (you might try several other networks). If the pings are successful or if you can contact some remote networks and not others, then the problem is with the routing path between your network and the specific remote network. Use the traceroute/tracert commands to check the path to the problem network.

Ping the Default Gateway

If you cannot contact any remote network, ping the default gateway router. If the ping is successful but you still cannot contact any remote host, have the router administrator verify the router configuration. Check for broken links to the remote network, interfaces that have been shut down, and access control lists or other controls that might be blocking traffic.

You recently created a new network segment for the development department. Because the hosts are now on a different network segment, they can no longer contact the DHCP server. Both network segments are connected via a Cisco router. Which of the following would be the best action to take in order to fix the problem?

Implement an IP helper address on the router. When an IP helper address is implemented on the Cisco router, DHCP broadcasts are forwarded to the specified IP address of the DHCP server. This allows hosts in a different network segment to contact the DHCP server. Installing and configuring a new DHCP would work, but it would not be the best solution. A new DHCP server would introduce additional costs and management overhead. Configuring the router to forward broadcast messages exposes the network to denial-of-service attacks. Moving the DHCP server would introduce the same problem to hosts in the other network segment.

DHCP Server Functions

In addition to providing IP addresses, a DHCP server can also provide clients with additional IP configuration parameters using options. Commonly used DHCP options include the subnet mask, the default gateway address, and a DNS server address. The following levels of options can be configured: > Server options are applied to all computers that get an IP address from the DHCP server, regardless of which scope they obtain the address from (for example, if your organization has only one DNS server, then all DHCP clients need the same DNS server address.) > Scope options are applied to all computers that get an IP address from a particular scope on the DHCP server (for example, because scopes are associated with specific subnets, each scope needs to be configured with the appropriate default gateway address option.) > Client options are applied to a specific DHCP client. The client's MAC address is used to identify which system receives the option.

Manually Configured tunnel

In this configuration, tunnel endpoints are configured as point-to-point connections between devices. Because of the time and effort required for configuration, use manually configured tunnels only when you have a small number of sites that need to connect through the IPv4 internet or when you want to configure secure site-to-site associations. Manual tunneling: > Is configured between routers at different sites. > Requires dual stack routers as the tunnel endpoints, but is compatible with IPv6-only hosts. > Works through NAT. > Uses a static association of an IPv6 address to the IPv4 address of the destination tunnel endpoint.

5.9.8 Explore Network Communications

In this lab, you will discover important facts about network communications by using the ping or tracert command utility. On ITAdmin, the IP address is configured, but not a default gateway address. The following local network IP addresses are used in this lab: N/A Complete this lab as follows: 1. Right-click Start > Command Prompt (Admin) to open the command prompt. 2. At the command prompt, enter ping 192.168.0.30 and press Enter to ping Office1. 3. You can successfully ping the IP address of Office1 from ITAdmin. 4. Enter ping 199.92.0.33 and press Enter to ping Support. 5. You cannot ping Support from ITAdmin. Notice that the IP address for Support is on a different network (network 199.92.0.0 instead of network 192.168.0.0). Devices on the same local network must have IP addresses in the same network range. If you want to communicate with Support, you will need to change the IP address assigned to Support. 6. Enter ping 192.168.0.5 and press Enter to ping the router's internal interface. 7. You can successfully ping the router's internal interface from ITAdmin. Because ITAdmin and the router's address (192.168.0.5) are on the same network, the ping tests succeed. 8. Enter ping 163.128.78.93 and press Enter to ping the external DNS Server. 9. ITAdmin and the ISP are on a different network (network 192.168.0.0 and 163.128.78.0 respectively). Because ITAdmin does not have a default gateway set, it cannot communicate with devices on other networks. 10. Trace the path between Exec and the internet router's interface as follows: a. From the top navigation tabs, select Floor 1 Overview. b. Under Executive Office, select Exec. c. Right-click Start > Command Prompt (Admin) to open the command prompt. d. At the command prompt, enter tracert 198.28.56.1 and press Enter. 11. When you communicate with devices on other networks, the packets go first to the default gateway (the router between the two networks). The packets are sent to the router interface on the same network as the sending host and then to the next hop in the path as necessary. In this case, there are two IP addresses listed in the tracert output, but only one router (hop) between Exec and the internet router. The last address in the tracert output is the internet router. 12. Enter tracert 163.128.78.93 and press Enter to trace the path to one of the ISP's DNS servers. 13. When you trace the path between Exec and the ISP's DNS server, the path has additional hops. The first lines in the tracert output are the routers (hops) between Exec and the DNS server. The last address in the tracert output is the DNS server.

A user reports that he can't browse to a specific website on the internet. From his computer, you find that a ping test to the web server succeeds. A traceroute test shows 17 hops to the destination web server. What is the most likely cause of the problem?

Incorrect DNS server address In this scenario, a ping test to the website succeeds, while accessing the website through the browser does not work. Users type host names in the browser to go to websites, but host names must be translated to IP addresses by a DNS server. Either the workstation is using the wrong address for the DNS server, the DNS server is not available, or the DNS server does not have an entry for the website. Because the ping and traceroute tests work, you know that the IP address, subnet mask, and default gateway values are correct.

You manage a network that has multiple internal subnets. You connect a workstation to the 192.168.1.0/24 subnet. This workstation cannot communicate with any other host on the network. You run ipconfig /all and see the following: Ethernet adapter Local Area Connection: Connection-specific DNS Suffix. : mydomain.local Description . . . . . . . : Broadcom network adapter Physical Address . . . . . : 00-AA-BB-CC-74-EF DHCP Enabled. . . . . . . : No Autoconfiguration Enabled . . : Yes IPv4 Address. . . . . . . : 192.168.2.102(Preferred) Subnet Mask . . . . . . . : 255.255.255.0 Default Gateway. . . . . . : 192.168.1.1 DNS Servers . . . . . . . : 192.168.2.20 What is the most likely cause of the problem?

Incorrect IP address In this example, the IP address assigned to the host is on the wrong subnet. The host address is on the 192.168.2.0/24 subnet, but the other devices are using addresses on the 192.168.1.0 subnet (the scenario states that you are connecting the workstation to this subnet).

You manage a network that has multiple internal subnets. You connect a workstation to the 192.168.1.0/24 subnet. This workstation can communicate with some hosts on the private network, but not with other hosts. You run ipconfig /all and see the following: Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : mydomain.local Description . . . . . . . : Broadcom network adapter Physical Address. . . . . . : 00-AA-BB-CC-74-EF DHCP Enabled . . . . . . . : No Autoconfiguration Enabled. . . : Yes IPv4 Address . . . . . . . : 192.168.1.102(Preferred) Subnet Mask . . . . . . . : 255.255.255.0 Default Gateway. . . . . . . . . : 192.168.2.1 DNS Servers. . . . . . . . . . . : 192.168.2.20

Incorrect default gateway In this example, the default gateway address is incorrect. The default gateway address must be on the same subnet as the IP address for the host. The host address is on the 192.168.1.0/24 subnet, but the default gateway address is on the 192.168.2.0 subnet.

You manage a network that has multiple internal subnets. You connect a workstation to the 192.168.1.0/24 subnet. This workstation can communicate with some hosts on the private network, but not with other hosts. You run ipconfig /all and see the following: Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : mydomain.local Description . . . . . . . : Broadcom network adapter Physical Address. . . . . . : 00-AA-BB-CC-74-EF DHCP Enabled . . . . . . . : No Autoconfiguration Enabled. . . : Yes IPv4 Address . . . . . . . : 192.168.1.102(Preferred) Subnet Mask. . . . . . . . : 255.255.0.0 Default Gateway . . . . . . : 192.168.1.1 DNS Servers . . . . . . . : 192.168.1.20 | 192.168.1.27 What is the most likely cause of the problem?

Incorrect subnet mask In this example, the network is using a mask of 255.255.255.0 (24-bits), but the workstation is configured to use a mask of 255.255.0.0.

-v, -vv, -vvv

Increase the amount of packet information you get back.

Your Windows DHCP server had a default lease time of eight days. However, you have decided to reconfigure this DHCP server to dynamically assign IP addresses to DHCP clients using a lease duration of four days. What impact, if any, will this have on the network?

Increased network traffic Decreasing lease time does slightly increase network traffic because clients will have to renew their IP addresses more often. However, decreasing the lease time also makes it so that you use your addresses more efficiently. There is no correlation to bandwidth increase or router performance increase.

Which two of the following statements about the dynamic host configuration protocol (DHCP) are true?

It can deliver other configuration information in addition to IP addresses. A DHCP server assigns addresses to requesting hosts. DHCP servers deliver IP addresses as well as other host configuration information to network hosts. DHCP can be configured to assign any available address to a host, or it can assign a specific address to a specific host.

Configuring a DHCP Server

Keep in mind the following when configuring a DHCP Server: > The DHCP service needs to auto-start when the server boots. > The server must have a static IP address. > A MAC reservation is an association of a MAC address with a specific IP address. In other words, the client with the specified MAC address is assigned the same IP address each time it requests an address. > An IP reservation means you program MAC addresses into the DHCP server. When the DHCP server sees a certain host requesting an IP address based on its MAC, it will give you a specific IP address. For a DHCP server to deliver IP addresses, it must have a scope configured. A scope is the range of IP addresses that the DHCP server can assign to clients. A scope can also be called a pool. When working with scopes, remember the following: > There should be only one scope per network segment. > The scope must be activated before the DHCP server can assign addresses to clients. After you activate a scope, you should not change it. > A scope has a subnet mask that determines the subnet for a given IP address. You cannot change the subnet mask of an existing DHCP scope; to change the subnet mask used by a scope, you must delete and recreate the scope. > Lease duration values are part of the scope properties, and they determine the length of time a client can use an IP address leased through DHCP. *The DHCP server can also be configured with exclusions, which are specific addresses in the range that should not be assigned.

-i any

Listen on all interfaces to check for traffic traffic.

tcpdump -i any

Listen on any available interface.

tcpdump -i eth0

Listen on interface eth0.

-i eth0

Listen on the eth0 interface.

Additional Facts

Local computers have a cache of recently resolved DNS names. The cache holds the DNS name and its IP address. When you use a DNS name, the computer first checks its cache. If the name is in the cache, the corresponding IP address is used. This can cause problems if a host's IP address has changed. Old values in the cache might continue to be used temporarily, making communication via the DNS name impossible. To correct this problem on a Windows computer, run ipconfig /flushdns to delete the local DNS name cache.

Unicast

Messages are sent to a specific host address. The sending device must know the IP address of all recipients and must create a separate packet for each destination device.

Unicast

Messages are sent to a specific host address. The sending device must know the IP address of all recipients, and must create a separate packet for each destination device.

You have a server at work with a custom application installed. Connections to the server that use the custom application must use IPv6. The server is currently running IPv4. You are the only person who connects to the server, and you always use your Linux laptop for the connection. Your laptop supports both IPv4 and IPv6. The rest of your company network runs only IPv4. You need a cost-effective solution to allow your laptop to connect to the server. Your solution must also support communication through NAT servers. Which client software should you use to connect to the server?

Miredo On Linux, Miredo client software is used to implement Teredo tunneling. Teredo tunneling establishes a tunnel between individual hosts. Hosts must be dual-stack hosts so they can tunnel IPv6 packets inside IPv4 packets. Teredo works through NAT. ISATAP and 6to4 tunneling both require at least one router. Because you only need to tunnel between two individual computers, Teredo is a more economical choice. Use 4to6 to tunnel IPv4 packets through an IPv6 network.

Which of the following address types is shared by multiple hosts and used to form groups of computers that receive the same data stream?

Multicast A multicast address is an address that identifies a group of computers. Members of the group share the same multicast address. A unicast address is an address that identifies a single host. A broadcast address is an address that is sent to all hosts. Broadcast traffic is typically only forwarded within (but not between) a subnet. Simplex communication uses a single channel for both sending and receiving. Half-duplex uses a separate channel for sending and receiving, but the channels are shared by multiple devices and can only be used by a single device at a time.

Which type of address is the IP address 232.111.255.250?

Multicast The address 232.111.255.250 is a multicast address. A multicast address is an address that identifies a group of computers. Members of the group share the same multicast address. Multicast addresses are in the range of 224.0.0.0 to 239.255.255.255. A unicast address is an address that identifies a single host. A broadcast address is an address that is sent to all hosts. Broadcast addresses are the last possible address on a subnet (typically ending in 255). The private IPv4 address ranges are: > 10.0.0.1 to 10.255.255.254 > 172.16.0.1 to 172.31.255.254 > 192.168.0.1 to 192.168.255.254

Which address type is used for a video conference call consisting of multiple participants?

Multicast Unified communication (UC) systems typically use unicast network transmissions. An example of a unicast transmission is a one-on-one VoIP phone call. UC systems also support multicast transmissions. Examples of a multicast transmission are conference phone calls or video conference calls consisting of multiple users.

Multicast

Multicast addresses represent a dynamic group of hosts. Packets sent to a multicast address are sent to all interfaces identified by that address. If different multicast addresses are used for different functions, only the devices that need to participate in a particular function will respond to the multicast; devices that do not need to participate in the function will ignore the multicast. Details include the following: > All multicast addresses have an FF00::/8 prefix. > Multicast addresses that are restricted to the local link have only an FF02::/16 prefix. > Packets starting with FF02 are not forwarded by routers. Multicast addresses with an FF01::/16 prefix are restricted to a single node. The following are well-known multicast addresses: > FF02::1 is for all nodes on the local link. This is the equivalent of the IPv4 subnet broadcast address. FF01::1 is for all interfaces on a node. > FF02::2 is for all routers on the local link. FF01::2 is for all routers on node-local. > FF02::1:2 is for all DHCP servers or DHCP relay agents on the local link. DHCP relay agents forward these packets to other subnets. *There are no broadcast addresses in IPv6. IPv6 multicast addresses are used instead of broadcast addresses.

5.7.2 Multicast Facts

Multicasting creates logical groups of hosts—messages sent to the group are received by all group members. Multicasting is typically used for streaming video and audio applications, such as video conferencing. Without multicasting, messages sent to a specific group only use the following:

Listed below are several DNS record types. Match the record type on the left with its function on the right.

Points a host name to an IPv4 address. A Provides alternate names to hosts that already have a host record. CNAME Points an IP address to a host name. PTR Points a hostname to an IPv6 address. AAAA Identifies servers that can be used to deliver mail. MX Records are used to store entries for host names, IP addresses, and other information in the zone database. Below are some common DNS record types: > The A record maps an IPv4 (32-bit) DNS host name to an IP address. This is the most common resource record type. > The AAAA record maps an IPv6 (128-bit) DNS host name to an IP address. > The PTR record maps an IP address to a host name (in a manner of speaking, it points to an A record). > The MX record identifies servers that can be used to deliver email. > The CNAME record provides alternate names (or aliases) to hosts that already have a host record. Using a single A record with multiple CNAME records means that when the IP address changes, only the A record needs to be modified.

CorpServ is a small company with 14 client systems and a network printer. Because there are only a limited number of networked systems, you decide to use APIPA addressing for the network. With APIPA configured, all systems are able to communicate with each other, but you are having trouble configuring Internet access. What is the likely cause of the problem?

Private addresses cannot directly communicate to hosts outside the local subnet. APIPA assigns private addresses designed for use on single-subnet networks that do not use routers. If internet access is required, APIPA cannot be used to provide clients direct access to the internet. APIPA is enabled by default and will assign an address if the DHCP server is unavailable. APIPA assigns only an IP address and subnet mask. A default gateway and DNS servers are not required to access network resources.

dig host name | host host name

Queries a host. The default query is for A records. You can change the default search by appending one of the record types below to the end of the command: > a—address records > any—any type of record > mx—mail exchange records > ns—name server records > soa—sort of authority records > hinfo—host info records > axfr—all records in the zone > txt—text records E.X. dig www.vulture.com ns host www.vulture.com -t ns

dig @IP address or host name domain

Queries the root server at the IP address or host name for the domain's A records. You can change the default query type by appending a different record type to the end of the command. E.X. dig @192.168.1.1 vulture.com ns

Records

Records are used to store entries for host names, IP addresses, and other information in the zone database. Each host has at least one record in the DNS database that maps the host name to the IP address. Common resource records include: > The A (Host Address) record maps an IPv4 (32-bit) DNS host name to an IP address. This is the most common resource record type. > The AAAA (Quad-A) record maps an IPv6 (128-bit) DNS host name to an IP address. > The PTR (Pointer) record maps an IP address to a host name (by pointing to an A record). > The MX (Mail Exchanger) record identifies servers that can be used to deliver email. > The CNAME (Canonical Name) record provides alternate names (or aliases) to hosts that already have a host record. If you only use a single > A record with multiple CNAME records, when the IP address changes, you only have to modify the A record. > The NS (Name Server) resource record identifies all name servers that can perform name resolution for the zone. Typically, there is an entry for the primary server and all secondary servers for the zone (all authoritative DNS servers). > The SRV (Service Locator) record identifies the resources that provide a service. This allows clients to find services, such as domain controllers, through DNS. Windows automatically creates these records as needed. > The SPF (Sender Policy Framework) record identifies authorized email servers. SPF records are created using TXT records. DNS uses the SPF record to verify that the host that sent the mail is authorized to use the DNS name. > DKIM (Domain Keys Identified Mail) is an email authentication method that uses a digital signature to validate email and make it easier to identify spoofed emails. The sending mail server signs the email with the private key, and the receiving mail server uses the public key in the domain's DNS information to verify the signature. One domain can have several DKIM keys publicly listed in DNS, but each matching private key is only on one mail server. DKIM records are created using TXT records.

Records

Records are used to store entries for hostnames, IP addresses, and other information in the zone database. Each host has at least one record in the DNS database that maps the hostname to the IP address.

You have a Windows Server 2016 system that you want to use as a DHCP relay agent. Which Windows Server 2016 service would you use to do this?

Routing and Remote Access In Windows Server 2016, the DHCP Relay Agent role is enabled and configured using the Routing and Remote Access service. Before a Windows server can be used as a DHCP Relay Agent, the Routing and Remote Access service (RRAS) must be installed.

-q

Show less protocol information.

You are configuring the DHCP Relay Agent role on a Windows server. Which of the following is a required step for the configuration?

Specify which server network interface the agent listens on for DHCP messages. When configuring the DHCP Relay Agent role, you need to specify which server network interface the agent will listen on for DHCP messages. The ip helper-address command is used to configure DHCP relay on Cisco routers, not Windows servers. An RFC 1542-compliant router is not necessary for DHCP relay when using the Windows Server DHCP Relay Agent. Configuring the Windows server to be on the same subnet as the DHCP server would prevent the server from being able to relay DHCP messages from a different subnet.

Match the IPv6 address configuration method on the right with its definition on the left.

Static Full Assignment The entire 128-bit address and all other configuration information is statically assigned to the host. Static Partial Assignment The prefix is statically assigned, and the interface ID is derived from the MAC address. Stateless Autoconfiguration Clients automatically generate the interface ID and learn the subnet prefix and default gateway through the neighbor discovery protocol (NDP). Stateful DHCPv6 Provides each client with an IP address, default gateway, and other IP configuration information. Stateless DHCPv6 Supplies the client with the DNS server IP address only. Does not provide the client with an IP address, and does not track the status of each client.

Static (Manual) Assignment

Static addressing means that IP configuration information is manually configured on each host. Static addressing is best used in the following situations: > On networks with a very small number of hosts. > On networks that do not change often or that will not grow. > To permanently assign IP addresses to hosts that must always have the same address (such as printers, servers, or routers). > For hosts that cannot accept IP addresses from DHCP servers. > To reduce DHCP-related traffic. *Static addressing is very susceptible to configuration errors and duplicate IP address configuration errors. Static addressing disables both APIPA and DHCP functions on the host.

You manage a subnet that uses the subnet address 198.162.1.0/23. Which of the following best describes how addressing is configured for the subnet?

Supernetting The subnet address 198.162.1.0/23 is an example of a supernetted address. With supernetting, multiple smaller subnets are combined into a single larger subnet. Supernetting is performed by taking the default subnet mask and making it smaller (using less bits). For this address, the default subnet mask uses 24 bits (255.255.255.0). With supernetting, the mask is altered to use only 23 bits (255.255.254.0) to combine multiple subnets together. Subnetting is the process of dividing a larger network into smaller networks. With the subnet address in this example, a subnetted address would use a larger subnet mask (using more bits). A subnetted address might use 25 bits (255.255.255.128) or more to subdivide the network into multiple smaller subnets. Sometimes the term "subnetting" can be used to refer to both subnetting and supernetting. But in this example, supernetting better describes what is being done. Classful addressing uses the default subnet mask based on the address class. If classful addressing were used, the subnet would use a 24-bit mask. Private addresses are within the following ranges: > 10.0.0.1 to 10.255.255.254 > 172.16.0.1 to 172.31.255.254 > 192.168.0.1 to 192.168.255.254

Common Uses

TCPdump prints the contents of network packets. It can read packets from a network interface card or a previously captured packet file. TCPdump can write packets to standard output or a file. You can TCPdump to intercept and display the network traffic of another user or computer, including user credentials, the content of packets, and other unencrypted information.

Teredo Tunneling

Teredo tunneling establishes a tunnel between individual hosts so they can communicate through a private or public IPv4 network. Teredo tunneling: > Is configured between individual hosts. > Uses dual stack hosts and performs IPv6 tunneling to send on the IPv4 network. > Works through NAT. In Windows 7, the Teredo component is enabled but inactive by default. In Windows 8, Teredo is enabled by default on work and home network profiles. On Linux, the Miredo client software is used to implement Teredo tunneling.

tracert or traceroute

Tests the route between your workstation and the DNS server. E.X. tracert 8.8.4.4

. (dot) domain

The . (dot) domain, or root domain, denotes a fully qualified, unambiguous domain name.

DHCP ACK (A)

The DHCP server responds to the request by sending a DHCP ACK (acknowledgement). At this point, the IP address is leased to and configured on the DHCP client. *If the DHCP server is on a different subnet, additional configuration steps are required, since network routers drop the DHCP broadcast frames by default.

5.5.3 DNS Facts

The Domain Name System (DNS) is a hierarchical distributed database that maps logical host names to IP addresses. DNS is a distributed database because no one server holds all of the DNS information. Instead, multiple servers hold portions of the data as follows: > Each division of the database is held in a zone database file. > Zones typically contain one or more domains, although additional servers might hold information for child domains. > DNS servers hold zone files and process name resolution requests from client systems.

You have a small network connected to the internet as shown in the Exhibit. You need to configure the default gateway address on Wrk1 so that it can communicate with hosts on the internet. Which address would you use for the default gateway address?

The IP address assigned to Fa0/0 on Router1. When assigning the default gateway address, use the address of the router interface connected to the same network that is used to reach remote networks. In this scenario, the workstation must be configured with the IP address assigned to the Fa0/0 interface on Router1. This default gateway configuration allows the workstation to communicate with hosts on the other internal subnet as well as with hosts on the network. The IP address assigned to the switch is only used to remotely manage the switch. Packets sent to remote networks are not processed by the switch, but the frames are forwarded to the correct destination device. The Fa0/1 interface on Router1 is not on the same network as Wrk1, so cannot be used as its default gateway address. The Fa0/0 interface on Router2 would be the default gateway address for hosts connected to SwitchB.

IANA

The Internet Assigned Numbers Authority is a function of a nonprofit private American corporation that oversees global IP address allocation, autonomous system number allocation, root zone management in the Domain Name System, media types, and other Internet Protocol-related symbols and internet numbers.

IGMP

The Internet Group Management Protocol (IGMP) is used to identify group members and to forward multicast packets on to the segments where group members reside. IGMP routers keep track of the attached subnets that have group members, using the following process: 1. A router sends out a host membership query. This query is addressed to the IP address 224.0.0.1. - The address 224.0.0.1 is never assigned to a group because it is used for the query messages sent by routers. 2. Hosts that are members of any groups respond with a list of the groups they belong to. Each group is identified with a multicast IP address in the range of 224.0.0.0 to 239.255.255.255. 3. The router uses these responses to compile a list of the groups on the subnet that have group members. Routers do not keep track of individual hosts that are members of a group; they simply compile a list of groups on the subnet that have at least one member. 4. When a host joins a new group, it automatically sends a join group message to the router. When the last host in a group leaves the group, it sends a leave group message to the router. 5. The IGMP router reports to upstream routers that they have members of a specific group. - Upstream routers are the routers that exist between the router and the server that sends out the multicast data stream. They keep track of downstream routers that have group members.

Duplicate MAC Addresses

The MAC address is a 12-digit hexadecimal number (48 bits). This address is unique, so you should not have duplicate addresses on your network. However, it is possible for two hosts to have the same MAC address, due to spoofing, a mistake during manufacturing, or if users choose a self-assigned address instead of the vendor-assigned hardware address. This last one is more common when using main frame systems that communicate via MAC addresses rather than protocol addresses (IP addresses). An Ethernet switch keeps a table of which MAC addresses are attached to which ports. It uses the source address of frames it receives during the normal operation of the network to make the table. When the switch receives a frame, the source MAC is read and compared with the current table, and then added alongside whichever switch port it was received on. Therefore, if there are two hosts with the same MAC address, then the switch will update it's MAC table every time it receives a frame from either host. Reaching either host will be inconsistent and cause other problems as well.

5.5.5 Create Standard DNS Zones

The accounting department is testing a new payroll system server. To facilitate their tests, they would like to add the payroll server to DNS to support name resolution. You need to create a new zone to support their request and accelerate lookups. You also need to place a copy of this zone on the DNS server in Building B. In this lab, your task is to complete the following: > Create a primary forward lookup zone on CorpDC using the following parameters: - Deselect Store the zone in Active Directory. - Use the zone name acct.CorpNet.com. - Use the default name for the zone file. - Do not allow dynamic updates. - Allow zone transfers to any server. > Create a secondary forward lookup zone called acct.CorpNet.com on CorpDC3. - Specify CorpDC (192.168.0.11) as the master DNS server for the zone *For your convenience, all DNS servers are available through the DNS Manager console on CorpDC. You can also use the navigation tabs to access each server and its console directly. Complete this lab as follows: 1. Create a primary forward lookup zone as follows: a. In Hyper-V Manager, select CORPSERVER. b. Maximize the window to view all virtual machines. c. Right-click CorpDC and select Connect (maximize the window for easier viewing if desired). d. In Server Manager, select Tools > DNS. e. Expand the DNS server that will host the zone. f. Right-click Forward Lookup Zones and select New Zone. g. In the New Zone wizard, select Next. h. Make sure Primary zone is selected. i. Unmark Store the zone in Active Directory (this option is only available for domain controllers); then select Next. j. In the Zone name field, enter: - Zone name: acct.CorpNet for the zone; then select Next. *Select Do not allow dynamic updates k. Verify that Create a new file with this file name is selected; then and select Next. l. Specify the updates that will be accepted for the DNS zone; then select Next. m. Select Finish to complete the New Zone wizard. 2. Configure zone transfer as follows: a. Under Forward Lookup Zones, right-click the new zone and select Properties. b. Select the Zone Transfers tab. c. Verify that Allow zone transfers is selected. d. Select To any server. e. Select OK. *Allow zone transfers to any server *Zone name: acct.CorpNet Zone type: Secondary *Configure CorpDC (192.168.0.11) as the master server for the zone 3. Create a Forward Secondary Zone as follows: a. From DNS Manager, expand the server that will host the new zone. b. Right-click Forward Lookup Zones and select New Zone. c. Select Next. d. On the Zone Type dialog, select Secondary zone as the zone type; then select Next. e. Enter the primary zone name; then select Next. f. In the Master Servers box, select Click here below IP Address. g. Enter the IP address or the name of a server that hosts a copy of the zone. h. Press Enter or click away from the IP address to begin validation. i. After it is validated, select Next. j. Click Finish to complete the New Zone wizard.

5.6.2 IPv6 Facts

The addresses available under the current IPv4 addressing standard have been exhausted. In response to this situation, a new IP addressing system (IP version 6, or IPv6) has been developed. An IPv6 address is a 128-bit binary number. A sample IPv6 IP address looks like the following: 35BC:FA77:4898:DAFC:200C:FBBC:A007:8973.

DHCP Discover (D)

The client begins by sending out a DHCP Discover frame to identify DHCP servers on the network.

After installing a new DHCP server on the network, you need to verify that network devices are receiving IP addressing via DHCP. You reboot a Windows 10 client system and using the ipconfig /all command, receive the following information: Ethernet adapter Local Area Connection 1: Description . . . . . . . . . . . : Intel(R) Ethernet Connection Physical Address. . . . . . . . . : 02-00-4C-4F-3F-50 DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Autoconfiguration IPv4 Address. . : 169.254.25.129 Subnet Mask . . . . . . . . . . . : 255.255.0.0 Default Gateway . . . . . . . . . : DNS Servers . . . . . . . . . . . : Which of the following statements are true? (Select two).

The client system is configured to use DHCP. The client system is unable to reach the DHCP server. A system configured as a DHCP client will attempt to locate a DHCP server during the boot process. If the client system is unable to locate the DHCP server and obtain IP information, an APIPA assigned address will be used. The client also configures itself with a class B subnet mask of 255.255.0.0. The output from the ipconfig command shows that the client system has been configured to receive IP information from a DHCP server. As such, the client system attempted to locate the DHCP server. When it couldn't, received the APIPA address of 169.254.25.129 and a subnet mask of 255.255.0.0. The default gateway does not have to be present to access a DHCP server.

Due to widespread network expansion, you have decided to upgrade the network by configuring a DHCP server. The network uses Linux, Windows, and Mac OS X client systems. You configure the server to distribute IP addresses from 192.168.2.1 to 192.168.2.100. You use the subnet mask of 255.255.255.0. After making all setting changes on the DHCP server, you reboot each client system, but they are not able to obtain an IP address from the DHCP server. Which of the following would explain the failure?

The clients must be configured to obtain IP addressing from a DHCP server. Once a DHCP server has been configured for the network, each client system has to be told to look for a DHCP server to obtain its IP addressing. Selecting DHCP to obtain IP addressing information is typically as easy as selecting a radio button. If the client is not set to DHCP, it will look for a statically assigned IP address. The DHCP service is supported by all major operating systems today. Using DHCP among different client systems would not be a problem. Rebooting the DHCP server would not be helpful if the client systems are not configured to use the DHCP service.

Prefix

The first 64 bits are known as the prefix. > The prefix can be divided into various parts that identify things such as geographic region, the ISP, the network, and the subnet. > The prefix length identifies the number of bits in the relevant portion of the prefix. To indicate the prefix length, add a slash (/) followed by the prefix length number. Full quartets with trailing 0s in the prefix address can be omitted (e.g., 2001:0DB8:4898:DAFC::/64). > Because addresses are allocated based on physical location, the prefix generally identifies the location of the host. The 64-bit prefix is often referred to as the global routing prefix.

Network

The first address in an address range is used to identify the network itself. For the network address, the host portion of the address contains all 0s. For example: > Class A network address: 115.0.0.0 > Class B network address: 154.90.0.0 > Class C network address: 221.65.244.0

DNS Facts

The following are some additional facts about DNS: > A forward lookup finds the IP address for a given host name. A reverse lookup finds the host name from a given IP address. > Root DNS servers hold information for the root zone ( . ). Root servers answer name resolution requests by supplying the address of the corresponding top-level DNS server (servers authoritative for .com, .edu, and similar domains). > On very small networks, you could configure a HOSTS file with several entries to provide limited name resolution services. However, you would have to copy the HOSTS file to each client. The work involved in this solution is only suitable for temporary testing purposes or for overriding information that might be received from a DNS server. > On the client, you should configure a list of DNS suffixes you want to append to unqualified DNS names submitted by clients for resolution as follows: - Configure a single DNS suffix for clients using a DHCP option on the DHCP server. - Configure multiple suffixes by adding them to the client manually.

Features of an IPv6 Address

The following list describes the features of an IPv6 address: > It is made up of 32 hexadecimal numbers organized into 8 quartets. > The quartets are separated by colons. > Each quartet is represented as a hexadecimal number between 0 and FFFF. Each quartet represents 16 bits of data (FFFF = 1111 1111 1111 1111). > Leading zeros can be omitted in each section. For example, the quartet 0284 could also be written as 284. > An address with consecutive zeros can be expressed more concisely by substituting a double colon for the group of zeros. For example: - FEC0:0:0:0:78CD:1283:F398:23AB - FEC0::78CD:1283:F398:23AB (concise form) *This is also called address compression. Address compression is when you take a fully-notated IPv6 address and remove empty octets from it, replacing them with a colon. > If an address has more than one consecutive location where one or more quartets are all zeros, only one location can be abbreviated. For example, FEC2:0:0:0:78CA:0:0:23AB can be abbreviated as: - FEC2::78CA:0:0:23AB or - FEC2:0:0:0:78CA::23AB but not - FEC2::78CA::23AB > The 128-bit address contains two parts:

Multicast Stream

The following process is used when sending a multicast stream: 1. The sending server sends packets addressed to the multicast group. 2. Routers receive the multicast packets and check their lists of group members. - If the router is connected to a subnet that has group members, or if the subnet includes a downstream router with group members, the multicast packet is sent on that subnet. - If a subnet does not have any group members, the packet is not forwarded on that subnet. - If a router does not have any subnets with group members, the packet is dropped and not forwarded. 3. Each intermediary router performs the same tasks until the data stream eventually reaches the multicast client.

5.9.5 arp and netstat Facts

The following table lists several commands that you can use on a Windows system to gather information about network connections. *Local computers have a cache of recently used IP addresses and their corresponding MAC addresses. When a computer needs to contact another computer on its own subnet, it first checks its cache for an entry of the IP address. If the entry is found, the corresponding MAC address is used to communicate with the destination computer. The cache can cause problems if the MAC address for a computer has recently changed (for example, if the network interface card has been replaced). To correct a problem, use the netsh command to clear the ARP cache.

Troubleshooting Process

The following table lists several tasks you can perform to troubleshoot the reported connectivity problem. These steps trace the problem backward from the remote host to the local host. Depending on the situation, you might be able to troubleshoot the problem more efficiently by skipping some tests or changing the order in which you perform them (you might even complete them in reverse order).

IPv6 Deployment Strategies

The following table lists various strategies for deploying IPv6.

Fully Qualified Domain Name (FQDN)

The host name and all domain names separated by periods. The final period (which is for the root domain) is often omitted and only implied.

Host Name

The host name is the part of a domain name that represents a specific host. For example, "www" is the host name of www.example.com.

Hostname

The hostname is the part of a domain name that represents a specific host. For example, "www" is the hostname of www.example.com.

Intra-site Automatic Tunnel Addressing Protocol (ISATAP)

The intra-site automatic tunnel addressing protocol is a tunneling method that provides IPv6 communication over a private IPv4 network. ISATAP tunneling: > Is configured between individual hosts and an ISATAP router. > Requires a special dual stack ISATAP router to perform tunneling and dual stack or IPv6-only clients. Dual stack routers and hosts perform tunneling when communicating on the IPv4 network. > Does not work through NAT. > Automatically generates link-local addresses that includes the IPv4 address of each host. - The prefix is the well-known link-local prefix: FE80::/16. - The remaining prefix values are set to 0. - The first two quartets of the interface ID are set to 0000:5EFE. - The remaining two quartets use the IPv4 address written in either dotted decimal or hexadecimal notation. *For example, a host with the IPv4 address 192.168.12.155 would have the following IPv6 address when using ISATAP: FE80::5EFE:C0A8:0C9B (also designated as FE80::5EFE:192.168.12.155). Use ISATAP to begin a transition to IPv6 within a site. You can start by adding a single ISATAP router and configuring each host as an ISATAP client.

If dynamic DNS is being used, which of the following events will cause a dynamic update of the host records? (Select two.)

The ipconfig /registerdns command is entered on a workstation. The DHCP server renews an IP address lease. Dynamic DNS (DDNS) enables clients or the DHCP server to update records in the zone database automatically. Dynamic updates occur when: > A network host's IP address is added, released, or changed. > The DHCP server changes or renews an IP address lease. > The client's DNS information is manually changed using the ipconfig /registerdns command. Clearing a browser's cache has no effect on DNS records. Because MX records and CNAME records need to be manually added and created, they have no effect on DDNS.

Interface ID

The last 64 bits are known as the interface ID. This is the unique address assigned to an interface. > Addresses are assigned to interfaces (network connections), not to the host. Technically, the interface ID is not a host address. > In most cases, individual interface IDs are not assigned by ISPs but are rather generated automatically or managed by site administrators. > Interface IDs must be unique within a subnet, but they can be the same if they are on different subnets. > On Ethernet networks, the interface ID can be automatically derived from the MAC address. Using the automatic host ID simplifies administration. To ensure that the interface ID is unique for every host on the network, IPv6 uses the Extended Unique Identifier 64 (EUI-64) format. The following are some details of the EUI-64 format: > To ensure that the interface ID is unique for every host on the network, IPv6 uses the Extended Unique Identifier 64 (EUI-64) format. The following are some details of the EUI-64 format: 1. Splitting the MAC address into 24-bit halves. 2. Inserting 16 bits (represented by hex FFFE) between the two halves *For example, a host with a MAC address of 20-0C-FB-BC-A0-07 would start with the following EUI-64 interface ID: 200C:FBFF:FEBC:A007. 3. To be complete, the EUI-64 format requires setting the seventh bit in the first byte to binary 1 (reading from left to right, this is the second hex value in the interface ID). This bit is called the universal/local (U/L) bit. - When the U/L bit is set to 0, the MAC address is a burned-in MAC address. - When the U/L bit is set to 1, the MAC address has been configured locally. EUI-64 requires the U/L bit to be set to 1. > Review the following examples: - 200C:FBFF:FEBC:A007 (Incorrect interface ID, as the U/L bit is still set to 0) - 220C:FBFF:FEBC:A007 (Correct interface ID) IPv6 adds the following features not included in IPv4:

Broadcast

The last address in the range is the broadcast address, and it is used to send messages to all hosts on the network. In binary form, the broadcast address has all 1s in the host portion of the address. For example, assuming the default subnet masks are used: > 115.255.255.255 is the broadcast address for network 115.0.0.0 > 154.90.255.255 is the broadcast address for network 154.90.0.0 > 221.65.244.255 is the broadcast address for network 221.65.244.0 *The broadcast address might also be designated by setting each of the network address bits to 0. For example, 0.0.255.255 is the broadcast address of a Class B address. This designation means "the broadcast address for this network."

Top-Level Domain (TDL)

The last part of a domain name (for example, .com, .edu, .gov). TDLs are managed by the Internet Corporation of Assigned Names and Numbers (ICANN).

Prefix ID

The leftmost bits of the IPv6 address, also know as the network ID. The prefix is used for routing IPv6 packets.

Local Loopback

The local loopback address for the local host is 0:0:0:0:0:0:0:1 (also identified as ::1 or ::1/128). The local loopback address is not assigned to an interface. It can verify that the TCP/IP protocol stack is properly installed on the host.

Loopback

The local loopback address for the local host is 0:0:0:0:0:0:0:1 (also identified as ::1 or ::1/128). The local loopback address is not assigned to an interface. It can verify that the TCP/IP protocol stack is properly installed on the host.

Static Partial Assignment

The prefix is statically assigned. The interface ID is derived from the MAC address.

Supernetting

The process of combining two or more networks.

Subnetting

The process of dividing a large network into smaller networks.

Interface ID

The rightmost bits of the IPv6 address used to uniquely identify a network card (interface) in a host.

192.168.0.10

The sales department wants to create an intranet for all sales employees. Internet Information Services (IIS) is installed on CorpWeb and will be used to host the intranet site. Employees need the ability to access the web server using any of the following URLs: > http://sales.private > http://intranet.sales.private > http://www.sales.private You created the sales.private zone on the CorpDC server. Now you need to allow clients to connect to the web server by creating the following records in the zone: > Create an ALIAS (CNAME) record leaving the name blank. (This allows users to connect to the server using the sales.private URL.) > Create an ALIAS (CNAME) record named intranet. > Create an ALIAS (CNAME) record named www. *When creating ALIAS records, use CorpWeb.CorpNet.com as the fully qualified domain name. Complete this lab as follows: 1. In Hyper-V Manager, select CORPSERVER. 2. Right-click CorpDC and select Connect. 3. In Server Manager, select Tools > DNS. 4. Expand CORPDC. 5. Expand the Forward Lookup Zones. 6. Right-click the sales.private zone and select New Alias (CNAME). 7. In the Alias name field, enter the alias name (to use the parent domain name for the alias, leave the field blank). 8. Enter the fully qualified domain name of the host. 9. Click OK. 10. Repeat steps 6-9 to create additional records.

Options

These are some of the many configuration options for TCPdump. For a complete list of options refer to the TCPdump MAN (manual) page.

Which of the following are characteristics of Teredo tunneling? (Select three.)

Tunnel endpoints configured on hosts. Dual stack hosts. Works through NAT.

Tunneling

Tunneling allows IPv6 hosts or sites to communicate over the existing IPv4 infrastructure. A device encapsulates IPv6 packets within IPv4 packets for transmission across an IPv4 network, and then the IPv6 packets are de-encapsulated by another device at the other end.

Tunneling

Tunneling allows IPv6 hosts or sites to communicate over the existing IPv4 infrastructure. A device encapsulates IPv6 packets within IPv4 packets for transmission across an IPv4 network, and then the IPv6 packets are de-encapsulated by another device at the other end. Tunneling solutions include the following:

Which type of address is used in a packet to address the packet to a single host?

Unicast A unicast address is an address that identifies a single host. A broadcast address is an address that is sent to all hosts. Broadcast traffic is typically only forwarded within (but not between) a subnet. A multicast address is an address that identifies a group of computers. Members of the group share the same multicast address. Simplex communication uses a single channel for both sending and receiving. Full-duplex has a dedicated send and receive channel between any two hosts.

Which type of address is the IP address 198.162.12.254/24?

Unicast The address 198.162.12.254 is a unicast address that identifies a single host on the 198.162.12.0 subnet. 198.162.12.255 is the broadcast address for the subnet. Multicast addresses are in the range of 224.0.0.0 to 239.255.255.255.

Unicast

Unicast addresses are assigned to a single interface for the purpose of allowing one host to send and receive data. Packets sent to a unicast address are delivered to the interface identified by that address. There are three types of unicast IPv6 addresses:

Unique local

Unique local addresses are private addresses used for communication within a site or between a limited number of sites. In other words, unique local addressing is commonly used for network communications that do not cross a public network; they are the equivalent of private addressing in IPv4. Details include the following: > Because unique local addresses are not registered with IANA, they cannot be used on a public network without address translation. > Addresses beginning with a prefix of FC00 or FD00 are unique local addresses. > Following the prefix, the next 40 bits are used for the Global ID. The Global ID is generated randomly, creating a high probability of uniqueness on the entire internet. > Following the Global ID, the remaining 16 bits in the prefix are used for subnet information. > Unique local addresses are likely to be globally unique, but they are not globally routable. Unique local addresses might be routed between sites by a local ISP. The process for designing a network addressing scheme when using unique local addresses is similar to that used for global unicast addresses. The key difference is how the prefix is defined. Because the address range is not registered, a global routing prefix does not have to be requested from an ISP. Instead, each organization defines its own prefix.

Which of the following strategies are used to prevent duplicate IP addresses being used on a network? (Select two.)

Use Automatic Private IP Addressing. Install a DHCP server on the network. To avoid duplicate IP addresses being used by network systems, automatic IP assignment is used. Both the DHCP service and APIPA can automatically assign addresses to client systems. Clients configured to use static IP addressing may inadvertently have duplicate IP addresses assigned to them. In such a case, one of the systems will not be able to log on to the network.

Which of the following terms are often synonymous with or made possible with CIDR? (Select two.)

VLSM Classless Classless inter-domain routing (CIDR) allows non-default subnet masks (variable-length subnet masks, or VLSMs). Routers use the following information to identify networks: > The beginning network address in the range. > The number of bits used in the subnet mask. For example, the subnet 199.70.0.0 with a mask of 255.255.0.0 is represented as 199.70.0.0/16 (16 being the number of 1 bits in the subnet mask). Classful addresses rely on the IP address class to identify the subnet mask. Network address translation (NAT) allows you to connect a private network to the internet without obtaining registered addresses for every host. Private addresses are translated to the public address of the NAT router. OSPF is a routing protocol that supports CIDR features.

IPv6 Configuration Process

When a host starts up, it uses the following process to configure the IPv6 address for each interface: 1. The host generates an IPv6 address using the link-local prefix (FE80::/10) and modifies the MAC address to get the interface ID. For example, if the MAC address is 20-0C-FB-BC-A0-07, the link-local address for the interface is FE80::220C:FBFF:FEBC:A007. 2. The host sends a neighbor solicitation (NS) message addressed to its own link-local address to see if the address it has chosen is already in use: > If the address is in use, the other network host responds with a neighbor advertisement (NA) message. The process stops, and you must configure the host manually. > If the address is not in use (no NA message is received), the process continues. 3. The host waits for an RA message from a router to learn the prefix: > If an RA message is not received, the host uses the multicast address FF02::2 to send an RS message addressed to all routers on the subnet. > The router sends an RA message addressed to all interfaces on the subnet using the multicast address FF02::1. > If no routers respond, the host attempts to use stateful DHCPv6 to receive configuration information. 4. The RA message contains information that identifies how the IPv6 address and other information should be configured. The following table shows possible combinations: > Stateful Autoconfiguration - Obtains the interface ID, subnet prefix, default gateway, and other configuration information from a DHCPv6 server. *The host sends a REQUEST message addressed to the multicast address FF02::1:2, requesting this information from the DHCPv6 server. > Stateless Autoconfiguration: - Sets the interface ID automatically. - Obtains the subnet prefix and default gateway from the RA message. - Obtains DNS and other configuration information from a DHCPv6 server. *The host sends out an INFORMATION-REQUEST message addressed to the multicast address FF02::1:2, requesting this information from the DHCPv6 server. 5. If a manual address or stateful autoconfiguration is used, the host sends an NS message to make sure the address is not already in use. If stateless autoconfiguration is used, the NS message is unnecessary because the interface ID was verified in step 2.

VLSM

When using VLSM, you ignore the default subnet mask boundaries and specify a custom number of subnet mask bits. For example, you could define a subnet mask of 255.255.252.0. In addition to the first and second octets, this mask also assigns the first six bits in the third octet to be used for the network portion of the address. This mask would appear in binary notation as follows: 11111111.11111111.11111100.00000000 As you can see, the six bits are reallocated from the host address to the network address. This allows you to create additional subnets, but it reduces the number of host addresses available within each one. For example, suppose your network is composed of four separate physical network segments connected by routers. The network uses the 10.0.0.0 private IP addressing scheme, but you want to divide the 10.0.0.0 network into four separate subnets. Under classful addressing, this network would use the first octet for the network address and the last three octets for node addresses. However you need to divide this large network into four subnets. To do this, you need to reconfigure the subnet mask to include the first two bits of the second octet, creating four additional networks. Instead of using the default Class A subnet mask of 11111111.00000000.00000000.00000000 (255.0.0.0), you use a subnet mask of 11111111.11000000.00000000.00000000 (255.192.0.0). Using CIDR notation, you can specify a prefix of /10 to indicate you are using 10 bits for the subnet mask. The following are four possible values in the IP address for the two extra bits that have been added to the subnet mask: 00 = 0 01 = 64 10 = 128 11 = 192 *On the internet, you can access many subnet calculators to calculate subnet boundaries, host addresses, and broadcast addresses. These values define the lower and upper boundaries for the four subnets created by the classless subnet mask, as shown in the following table:

Host Addresses

When you are assigning IP addresses to hosts, understand the following: > Each host must have a unique IP address. > Each host on the same network must have an IP address with a common network portion of the address. You must use the same subnet mask when configuring addresses for hosts on the same network. The range of IP addresses available for network hosts is identified by the subnet mask and/or the address class. When assigning IP addresses to hosts, be aware that you cannot use the first or last addresses in the range (these are reserved for the network and broadcast addresses respectively). For example: > For the class A network address 115.0.0.0, the host range is 115.0.0.1 to 115.255.255.254. > For the class B network address 154.90.0.0, the host range is 154.90.0.1 to 154.90.255.254. > For the class C network address 221.65.244.0, the host range is 221.65.244.1 to 221.65.244.254. *Another way to identify a host on a network is to set the network portion of the address to all 0s. For example, the address 0.0.64.128 means "host 64.128 on this network."

Recursion Process

When you use the host name of a computer (for example, if you type a URL such as www.mydomain.com), recursion is employed to find the IP address. Recursion is the process by which a DNS server uses root name servers and other DNS servers to perform name resolution. The following steps occur: 1. The host looks in its local cache to see if it has recently resolved the host name. 2. If the information is not in the cache, it checks the Hosts file. The Hosts file is a static text file that contains host-name-to-IP address mappings. 3. If the IP address is not found, the host contacts its preferred DNS server. If the preferred DNS server can't be contacted, the host continues contacting additional DNS servers until one responds. 4. The host sends the name information to the DNS server. The DNS server checks its cache and Hosts file. If the information is not found, the DNS server checks any zone files that it holds for the requested name. 5. If the DNS server can't find the name in its zones, it forwards the request to a root zone name server. This server returns the IP address of a DNS server that has information for the corresponding top-level domain (such as .com). 6. The first DNS server requests the information from the top-level domain server. The server returns the address of a DNS server with the information for the next highest domain. This process continues until a DNS server is contacted that holds the necessary information. 7. The DNS server places the information in its cache and returns the IP address to the client host. The client host also places the information in its cache and uses the IP address to contact the desired destination device.

6-to-4 Tunneling

With 6-to-4 tunneling, tunneling endpoints are configured automatically between devices. Use 6-to-4 tunneling to dynamically connect multiple sites through the IPv4 internet. Because of its dynamic configuration, 6-to-4 tunneling is easier to administer than manual tunneling. 6-to-4 tunneling: > Is configured between routers at different sites. > Requires dual stack routers as the tunnel endpoints, but can work with IPv6-only hosts. > Works through NAT. > Uses a dynamic association of an IPv6 site prefix to the IPv4 address of the destination tunnel endpoint. > Automatically generates an IPv6 address for the site using the 2002::/16 prefix followed by the public IPv4 address of the tunnel endpoint router. For example, a router with an IPv4 address of 207.142.131.202 would serve the site with the following prefix: 2002:CF8E:83CA::/48 (CF8E:83CA is the hexadecimal equivalent of 207.142.131.202).

5.8.8 Troubleshoot IP Configuration 3

You are a network technician for a small corporate network. The network is connected to the internet and uses DHCP for address assignment. The employee in Office 1 reports that his workstation can communicate with some computers on the network, but not on the internet. You need to diagnose and fix the problem. In this lab, your task is to complete the following: > Use the following troubleshooting tools to diagnose the problem in the network: - The ping, ipconfig, or tracert command utility - The Network and Sharing Center in the Windows 10 or Windows Server 2016 operating system - The DHCP server console in the Windows Server 2016 operating system > Fix the problem at the workstation, the DHCP server, or both as necessary. > Use the troubleshooting tools to confirm that the problem is resolved. *To see the network diagram and wiring schematics of the network, use Exhibits. Complete this lab as follows: 1. In Office 1, begin troubleshooting the problem by verifying the scope of the connectivity problem. a. From the workstation, ping CorpServer in the Networking Closet. b. Ping the Internet Service Provider (ISP) (Notice that the ping fails for both CorpServer and the ISP). 2. In the IT Administration office, verify the connectivity problem between the workstation and all other workstations in the network (the ping to all other workstations in the network and the ISP succeeds). Both steps 1 and 2 confirm that there is not a physical connectivity problem in the local network and that the scope of the problem is most likely related to the IP configuration for the Office 1 workstation. 3. On Office 1, open the command prompt and enter the ipconfig /all command to check the Ethernet configuration. You should notice the following problems: - The subnet mask is incorrectly configured with 255.255.255.240. The workstation can only communicate with other hosts whose IP addresses have the same network address as determined by the local subnet mask. ITAdmin is 192.168.0.20, and Office 1 is 192.168.0.30. With 255.255.255.240 as a subnet mask, the network would only include addresses from 192.168.0.16 to 192.168.0.31. The IP address for CorpServer (192.168.0.10) and the router fall outside of this range. - The DHCP Enabled line shows No. This means that the workstation has been configured with a static IP address. - The DNS Servers line shows 163.128.78.108, which is not the address of either of the External DNS Servers. 4. On Office 1, configure the network connection to request the IP address information from the DHCP server: a. Right-click the Network icon and select Open Network and Sharing Center. b. Select Ethernet. c. Select Properties. d. Select Internet Protocol Version 4 (TCP/IPv4). e. Select Properties. f. Select Obtain an IP address automatically. g. Select Obtain DNS server address automatically. h. Select OK. i. Select Close. j. Select Close. 5. On Office 1, open the command prompt and enter ipconfig /all to check the Ethernet configuration. You should notice the line for DHCP Enabled shows Yes, a new IP address, the correct subnet mask, and the correct DNS Server. 6. Confirm the resolution of the problem by pinging the ISP. The ping to the ISP succeeds.

5.8.6 Troubleshoot IP Configuration 1

You are a network technician for a small corporate network. The network is connected to the internet and uses DHCP for address assignment. The employees in the Support Office and Office 2 report that their workstations can communicate with some computers on the network, but not on the internet. You need to diagnose and fix the problem. In this lab, your task is to complete the following: > Use the following troubleshooting tools to diagnose the problem in the network: - The ping, ipconfig, or tracert command utility - The Network and Sharing Center in the Windows 10 or Windows Server 2016 operating system - The DHCP server console in the Windows Server 2016 operating system > Fix the problem at the workstation, the DHCP server, or both as necessary. > Use the troubleshooting tools to confirm the resolution of the problem. *To see the network diagram and the wiring schematics of the network, use Exhibits. Complete this lab as follows: 1. In the Support Office, begin troubleshooting the problem by verifying the scope of the connectivity problem. From the workstation, ping the computer in the Networking Closet and ping the internet service provider (ISP) (pinging the computer in the Networking Closet succeeds, but the ping to the ISP fails). 2. In Office 2, verify the connectivity problem between the workstation and all other workstations in the network (the ping to all other workstations in the network succeeds, but the ping to the ISP fails). Both steps 1 and 2 confirm that there is not a physical connectivity problem in the local network. The problem is most likely related to the IP configuration for the network. 3. In the Support Office, open the command prompt and enter ipconfig /all to check the Local Area Connection configuration. You should notice the following problems: a. The default gateway address is incorrectly configured with 192.168.0.4. This is why the workstation in this scenario can only communicate with hosts on the local network, but not on the internet. b. The DHCP Enabled line is Yes, meaning that the workstation is configured to use a DHCP server. c. The DHCP server address listed is 192.168.0.10. This is the correct DHCP server address. The workstation received addressing and default gateway information from the correct DHCP server. Therefore, the DHCP server has been configured to give out the wrong default gateway address. 4. In the Networking Closet computer on CorpServer, open the CorpDHCP guest server and launch the DHCP console to reconfigure the settings for the DHCP scope as follows: a. In Hyper-V Manager, select CORPSERVER. Expand the window to view all virtual machines. b. Right-click CorpDHCP and select Connect. c. In Server Manager, select Tools > DHCP to start the DHCP console. d. Expand CorpDHCP. e. Expand IPv4. f. Expand Scope [192.168.0.1] Subnet1. g. Select Scope Options. h. Right-click 003 Router. i. Select Properties. j. In the default gateway address field, enter 192.168.0.5 and remove 192.168.0.4. k. Click OK to apply the change. 5. In the Support Office, open the command prompt and enter ipconfig /renew. This will request the new IP address information from the DHCP server and reconfigure the settings for the Ethernet connection. 6. Enter ipconfig /all to check the Ethernet configuration. You should notice the line for the default gateway is now correctly configured as 192.168.0.5. 7. Confirm the resolution of the problem by pinging the ISP. The ping to the ISP succeeds. 8. In Office 2, repeat steps 5-7 to fix the problem for the second workstation.

5.8.7 Troubleshoot IP Configuration 2

You are a network technician for a small corporate network. The network is connected to the internet and uses DHCP for address assignment. The owner of the company in the Executive Office and a temporary employee in IT Administrator office both report that their workstations can communicate with some computers on the network, but cannot communicate with the internet. You need to diagnose and fix the problem. In this lab, your task is to complete the following: > Use the following troubleshooting tools to diagnose the problem in the network: - The ping, ipconfig, or tracert command utility - The Network and Sharing Center in the Windows 10 or Windows Server 2016 operating system - The DHCP server console in the Windows Server 2016 operating system > Fix the problem at the workstation, the DHCP server, or both as necessary. > Use the troubleshooting tools to confirm the resolution of the problem. *To see the network diagram and the wiring schematics of the network, use Exhibits. Complete this lab as follows: 1. In the Executive Office, begin troubleshooting the problem by verifying the scope of the connectivity problem. From the workstation, ping the computer in the Networking Closet. The ping to the location fails. 2. Ping the Internet Service Provider (ISP). The ping to the location fails. 3. In the IT Administrator office, verify the connectivity problem between the workstation the Networking Closet computer and the ISP. (The pings to both locations fails). The problem is most likely related to the IP configuration for the network. 4. In the Executive Office, open the command prompt and use the ipconfig /all command to check the Local Area Connection configuration. You should notice the following problems: - The default gateway and DNS server addresses have not been configured on the workstation. This means that communication is limited to other computers on the local network. - The DHCP Enabled line is Yes, meaning that the workstation is configured to use a DHCP server. - The DHCP Server address line is not shown. This means that the workstation was unable to contact the DHCP server. - The IP address is in the APIPA range (169.254.0.1 to 169.254.255.254). This means that the workstation assigned itself an IP address. The workstation will be able to communicate with other hosts on the local network that have also configured their own IP address through APIPA. 5. In the Networking Closet, confirm that the DHCP service is enabled and activated for the local network. a. In Hyper-V Manager, select CORPSERVER. Expand the window to view all virtual machines. b. Right-click CorpDHCP and select Connect (maximize the window for easier viewing if desired). c. In Server Manager, select Tools > DHCP to start the DHCP console. d. Expand CorpDHCP.CorpNet.com. e. Expand IPv4. The down arrow for Scope [192.168.0.1] Subnet1 indicates that the scope is not active. f. Right-click Scope [192.168.0.1] Subnet1 and select Activate. The down arrow for the scope is gone, and the DHCP service for the local network is now active. 6. In the Executive Office, open the command prompt and enter ipconfig /renew. This will request the new IP address information from the DHCP server, and it will reconfigure the settings for the Ethernet connection. 7. Enter ipconfig /all to check the Ethernet configuration. You should notice the lines for the default gateway, DNS server, and DHCP server are now configured, along with a new IP address within the DHCP scope for the local network. 8. In the Executive Office, confirm the resolution of the problem by pinging the ISP. The ping to the ISP succeeds. 9. In the IT Administrator Office, repeat step 6 to fix the problem for that workstation.

5.3.2 Configure a DHCP Server

You are a network technician for a small corporate network. You want to use DHCP to provide TCP/IP address information to the workstations in the network. You already have a Windows Server 2016 server named CorpDHCP installed and running as a guest on CorpServer in the Network Closet. You have installed the DHCP server role and now you are ready to configure an IPv4 scope. In this lab, your task is to complete the following: > On the CorpDHCP server (running as a guest on CorpServer in the Networking Closet), create a DHCP IPv4 scope with the following parameters: | N/A | > On CorpDHCP, activate the Subnet1 scope. > On Gst-Lap in the Lobby, confirm the DHCP scope settings by configuring the local area connection to obtain its IP and DNS addresses automatically from the DHCP server. Complete this lab as follows: 1. Configure and activate the IPv4 DHCP scope on server as follows: a. In Hyper-V Manager, select CORPSERVER. b. Resize the window to view all virtual machines. c. Right-click CorpDHCP and select Connect. d. Maximize the window for easier viewing e. In Server Manager, select Tools > DHCP. f. Expand the DHCP server. g. Right-click IPv4 and select New Scope. h. In the the New Scope Wizard, select Next. i. In the Name field, enter the scope name; then select Next. j. In the Start IP address field, enter the start IP address. k. In the End IP address field, enter the end IP address. l. Make sure that the length is correct. m. Make sure that the subnet mask is correct; then select Next. n. In the Add Exclusions and Delay window, select Next. o. Use the default lease duration and select Next. p. Make sure Yes, I want to configure these option now is selected; then click Next. q. In the IP address field, enter the default gateway address. r. Select Add; then click Next. s. In the IP address field, enter DNS server address. t. Select Add; then click Next. u. In the WINS Servers window, select Next. v. Make sure Yes, I want to activate this scope now is selected; then select Next. w. Click Finish to close the wizard and create the scope. 2. Configure the laptop in the Lobby to obtain IP and DNS addresses automatically from the DHCP server as follows: a. From the top, select Floor 1 Overview. b. Under Lobby, select Gst-Lap. c. In the notification area, right-click the Network icon and select Open Network and Sharing Center. d. Select Ethernet. e. In the Ethernet Status window, select Properties. f. Select Internet Protocol Version 4 (TCP/IPv4). g. Select Properties. h. Select Obtain an IP address automatically. i. Select Obtain DNS server address automatically. j. Select OK. kj. Click Close to close Ethernet Properties. l. Click Close to close Ethernet Status.

5.6.9 Configure an IPv6 Address

You are the IT administrator for a small corporate network. The company has obtained the registered globally unique IPv6 /48 network address 2620:14F0:45EA. You need to configure your server with this address so you can begin testing IPv6 in your internal network. This is your first network, so you will use a subnet address of 0001. Your network router is not configured for IPv6 yet, so you must manually configure the address for now. To simplify the configuration, use the server's IPv4 address to create the interface ID. In this lab, your task is to configure the external vEthernet network adapter with the following IPv6 address: > Prefix: 2620:14F0:45EA:0001 > Interface ID: 192:168:0:10 > Subnet prefix length: 64 Use ipconfig to verify the information. Complete this lab as follows: 1. Right-click the Network icon in the notification area and select Open Network and Sharing Center. 2. On the left, select Change adapter settings. 3. Right-click the vEthernet (External) adapter and select Properties. 4. Select Internet Protocol Version 6 (TCP/IPv6). 5. Select Properties. 6. Select Use the following IPv6 address. 7. In the IPv6 address field, enter 2620:14F0:45EA:0001:192:168:0:10 as the IPv6 address. 8. In the Subnet prefix length field, enter 64. 9. Click OK. 10. Click Close. 11. Right-click Start and select Command Prompt (Admin) to verify the address configuration. 12. Enter ipconfig /all and view the IPv6 Address.

5.10.4 Explore nslookup

You are the administrator for the CorpNet.com domain. The CorpDC and CorpDC3 servers are the DNS servers for the domain. CorpDC resides in Building A, and CorpDC3 resides in Building B. Users in Building B report that they are unable to contact the CorpWeb server. In this lab, your task is to complete the following: > Use nslookup to query DNS for the CorpWeb server using its full name (CorpWeb.CorpNet.com). What happens? > Use nslookup to query the CorpDC3 DNS server for CorpWeb. What happens? What is the problem? > How would you resolve this problem? > How would you verify that the problem has been fixed? Complete this lab as follows: 1. Right-click Start and select Command Prompt (Admin). 2. At the command prompt, enter nslookup CorpWeb.CorpNet.com and press Enter. The CorpDC DNS server responds with name resolution information for CorpWeb. 3. Enter nslookup CorpWeb.CorpNet.com CorpDC3.CorpNet.com and Press Enter. The CorpDC3 DNS server responds that it can't find CorpWeb. CorpDC3 does not have a DNS record for CorpWeb. The information between the DNS databases is not consistent. Since this DNS zone is an Active Directory-integrated zone, this indicates that Active Directory is not synchronizing properly. You would likely attempt to force replication between the Active Directory Domain Controllers. If CorpDC held a primary zone and CorpDC3 held a secondary zone, you would likely initiate a zone transfer to make sure the DNS records were consistent between servers. To verify that the problem has been fixed, you can repeat step 3. The CorpDC3 DNS server should responds with name resolution information for CorpWeb.

5.5.8 Troubleshoot DNS Records

You are the administrator for the CorpNet.com domain. The CorpDC and CorpDC3 servers are the DNS servers for the domain. You are responsible for CorpDC, which resides in Building A. Users report that they are unable to contact the CorpWeb server. In this lab, your task is to complete the following: > Ping the CorpWeb server using its full name of CorpWeb.CorpNet.com. What happens? > Ping the CorpWeb server using its IP address 192.168.0.15. What happens? > Create any DNS records needed to fix the problem. - Host name: CorpWeb - IP address: 192.168.0.15 > Use the ping command to verify that the problem is fixed. Complete this lab as follows: 1. Right-click Start and select select Command Prompt (Admin). 2. At the command prompt, enter ping CorpWeb.CorpNet.com and press Enter. Notice that the ping is unable to find CorpWeb. 3. Type ping 192.168.0.15 and press Enter. This time the ping succeeds using the IP address, indicating that there is a problem with the CorpWeb DNS record. 4. In Hyper-V Manager, select CORPSERVER. Resize the window to view all virtual machines. 5. Right-click CorpDC and select Connect (maximize the window for easier viewing if desired). 6. In Server Manager, select Tools > DNS. 7. Expand CORPDC. 8. Expand Forward Lookup Zones. 9. Right-click CorpNet.com and select New Host (A or AAAA). 10. In the Name field, enter CorpWeb. 11. In the IP Address field, enter the 192.168.0.15. 12. Select Create associated pointer (PTR) record to automatically create the PTR record for the new host. 13. Select Add Host. 14. Select OK. 15. Select Done to close the New Host dialog. 16. From the Command Prompt window on CorpServer, enter ping CorpWeb.CorpNet.com and press Enter. Now the ping succeeds.

Link-Local

You are troubleshooting a server that needs to connect directly to the Internet. After you run an ipconfig/all, you see that the server has been auto-assigned the IPv6 address fe80::260:8ff:fec0:98%4. The server won't connect to the Internet due to the fact that this is a _____ address.

5.8.4 Ipconfig Utility Facts

You can use ipconfig /all to troubleshoot IP configuration problems. The following table describes how the output for this command changes, based on how IP settings are configured and for specific problem situations:

5.4.4 Add a DHCP Server on Another Subnet

You have just authorized the CorpDHCP server to assign IP addresses to client workstations on the 192.168.10.0 subnet. Now you need to create an IPv4 scope on the CorpDHCP server for an address range on this subnet. In this lab, your task is to complete the following: > On CorpDHCP, create an IPv4 scope using the following specifications and activate the new scope upon completion: - IPv4 scope name: MySubnet - Address range: 192.168.10.21 to 192.168.10.199 - Default gateway: 192.168.10.5 - DNS Servers: 198.28.56.108 and 163.128.78.93 Complete this lab as follows: 1. From Hyper-V Manager, click CORPSERVER. Expand the window to view all virtual machines. 2. Right-click the CorpDCHP server and select Connect (maximize the window for easier viewing if desired). 3. From Server Manager, select Tools > DHCP. 4. Expand the CorpDHCP server node. 5. Right-click IPv4; then select New Scope. 6. Click Next. 7. In the Name field, enter MySubnet; then select Next. 8. In the Start IP address field, enter 192.168.10.21. 9. In the End IP address field, enter 192.168.10.199. 10. Click Next > Next > Next > Next. 11. For the Router address, enter 192.168.10.5; then click Add > Next. 12. For the first DNS Server, enter 198.28.56.108; then click Add. 13. For the second DNS Server, enter 163.128.78.93; then click Add. 14. Click Next > Next. 15. Leave the Yes, I want to activate this scope now option selected; then click Next. 16. Click Finish to complete the process of creating the DHCP scope.

5.3.5 Create DHCP Exclusions

You have just configured a scope on the CorpDHCP server to service the 192.168.0.0/24 subnet. You defined a scope to distribute IP addresses between 192.168.0.1 and 192.168.0.254. Now you need to prevent the DHCP server from assigning addresses to the servers and network devices. Create an exclusion range to exclude addresses 192.168.0.1 to 192.168.0.29 *Because all addresses that need to be excluded are in a contiguous ranges, you complete this task by creating an exclusion range. In this lab, create the exclusion on the Subnet1 subnet. Use 192.168.0.1 as the beginning address and 192.168.0.29 as the ending address of the exclusion. Complete this lab as follows: 1. From Hyper-V Manager, select CORPSERVER. 2. Expand the window to view all virtual machines. 3. Right-click the CorpDCHP server and select Connect. 4. From Server Manager, select Tools > DHCP. 5. In the left pane, expand the CorpDHCP.CorpNet.com. 6. Expand the IPv4 protocol. 7. Expand the Scope folder. 8. Right-click the Address Pool node and select New Exclusion Range. 9. In the Start IP address field, enter the starting IP address. 10. In the End IP address field, enter the ending IP address. 11. Click Add. 12. Click Close to close the Add Exclusion Range dialog.

5.3.4 Configure DHCP Options

You have just configured a scope on the CorpDHCP server to service the 192.168.0.0/24 subnet. You need to configure additional TCP/IP parameters for all clients serviced by the CorpDHCP server. In this lab, your task is to complete the following: > Configure the following DHCP options for the CorpDHCP server (not on the Subnet1 scope): - 006 DNS Servers = 192.168.0.11 and 192.168.10.11 (in that order) - 015 DNS Domain Name = CorpNet.com > Configure Subnet1 scope options as follows: - 003 Router (default gateway) as 192.168.0.5 Complete this lab as follows: 1. Configure DHCP server options as follows: a. From Hyper-V Manager, select CORPSERVER. b. Maximize the Hyper-V Manager window to view the available server. c. Right-click CorpDCHP and select Connect. d. From Server Manager, select Tools > DHCP. e. Expand CorpDHCP.CorpNet.com. f. Expand IPv4. g. Right-click Server Options and select Configure Options. g. Under Available Options, select the 006 DNS Servers. h. Under IP Address, enter the IP address. i. Select Add to add the IP address to the list. j. Repeat steps 1i-1j to add additional IP addresses. k. Click Apply. l. Under Available Options, select 015 DNS Domain Name. m. In the String value field, enter CorpNet.com. n. Click OK to save the options you have defined. 2. Configure DHCP scope options as follows: a. Expand Scope [192.168.0.1] Subnet1. b. Right-click Scope Options and select Configure Options c. Under Available Options, select the 003 Router. d. Under IP address, enter 192.168.0.5. e. Click Add to add the IP address to the list. f. Click OK to save the options you defined.

5.3.6 Create DHCP Client Reservations

You have several printers on Subnet1 that need static IP addresses assigned. In this lab, your task is to configure the CorpDHCP server so that these machines always get the same IP addresses. Additionally, configure each reservation for DHCP only. Use the values in the table below to configure the reservations. By default, the reservations are enabled for both DHCP and BootP. You must change the default setting to enable DHCP only. Complete this lab as follows: 1. From Hyper-V Manager, select CORPSERVER. 2. Expand the window to view all virtual machines. 3. Right-click the CorpDCHP server and select Connect. 4. From Server Manager, select Tools > DHCP. 5. In the left pane, expand the CorpDHCP.CorpNet.com. 6. Expand the IPv4 protocol. 7. Expand the Scope folder. 8. Right-click Reservations and select New Reservation. 9. In the Reservation name field, enter a reservation name (such as the computer name). 10. In the IP address field, enter the IP address. 11. In the MAC address field, enter the MAC address. For Ethernet, the MAC address will look like c8ba99cd8012 or c8-ba-99-cd-80-12. 12. Under Supported types, select DHCP only as needed. 13. Select Add to create the client reservation. 14. Repeat steps 9-13 for additional reservations. 15. Select Close.

When using the default subnet mask for an IP address:

You have the following number of subnet addresses and hosts per subnet: > There are only 126 Class A network IDs (most of these addresses are already assigned). Each class A address gives you 16,777,214 hosts per network. > There are 16,384 Class B network IDs. Each class B address gives you 65,534 hosts per network. > There are 2,097,152 Class C network IDs. Each class C address gives you 254 hosts per network. > Class D addresses are used for multicast groups rather than network and host IDs. > Class E addresses are reserved for experimental use.

You are implementing a DHCP server for your segment. Your segment's IP address is 192.168.1.0. Your default gateway address is 192.168.1.254. Your DNS server address is 192.168.1.1. Your default gateway is configured as a NAT router to translate addresses between network segments. You configured the 03 Router option on your DHCP server so it can deliver the IP address of the default gateway to workstations. After configuring your workstations to get their IP addressing information dynamically, your users complain that they are unable to access websites on the internet. How can you resolve this problem?

You must configure your DHCP server with an option that delivers the IP address of the DNS server (Option 06). In this scenario, the DHCP server hasn't been configured to deliver the IP address of the DNS server to the workstations. When users try to access websites with a browser, they receive an error message because their workstations can't resolve URLs into IP addresses. To fix this problem, you must enable the 06 Domain Name Server option on the DHCP server and configure it with the IP address of your DNS server. You could statically configure APIPA on each workstation with the IP address of the DNS server, but doing this would defeat the purpose of implementing a DHCP server in the first place.

5.3.8 Configure a DHCP Client

You work as the IT administrator for a small corporate network. The network uses a DHCP server for IP address configuration for most clients. In the Executive Office, the manager asked you to configure her laptop so that she can use it at home and at work. The laptop is currently configured with a static wireless connection for her home network, but the laptop is not connecting to the network while at the office. You need to configure the TCP/IP properties on the laptop to work on both networks. In this lab, your task is to complete the following: > Record the laptop's static IP and DNS configuration settings. > Configure the laptop to obtain IP and DNS addresses automatically. > Create an alternate TCP/IP connection with the static settings. Complete this lab as follows: 1. From the notification area, right-click the Network icon and select Open Network and Sharing Center. 2. Select Change adapter settings. 3. Right-click Wi-Fi. 4. Select Properties. 5. Select Internet Protocol Version 4 (TCP/IPv4). 6. Select Properties. 7. Record the current static values for the IP address, subnet mask, default gateway, and DNS server address. 8. Select Obtain an IP address automatically to use DHCP. 9. Select Obtain DNS server address automatically. 10. Select the Alternate Configuration tab. 11. Select User configured. 12. Enter the IP address, subnet mask, default gateway, and DNS server address you recorded in step 4. 13. Select OK. 14. Click Close. 192.168.2.13 255.255.255.0 192.168.2.254 192.168.2.254

5.2.3 Configure Alternate Addressing

You work as the IT administrator for a small corporate network. The receptionist in your office has a laptop that runs Windows 10. She took it home and configured a static connection to her home network. Now she cannot connect to the office network, which uses a DHCP server for IP address configuration. You need to configure the laptop to work on both networks. In this lab, your task is to configure the Internet Protocol Version 4 (TCP/IPv4) properties with the following settings: > On the General tab, set the following parameters: Obtain an IP address automatically Obtain DNS server address automatically > On the Alternate Configuration tab, set the following parameters: IP Address: 172.16.0.12 Subnet Mask: 255.255.0.0 Default Gateway: 172.16.255.254 Preferred DNS Server: 198.60.22.2 *The Alternate Configuration tab does not show up until Obtain an IP address automatically is selected. Complete this lab as follows: 1. In the notification area, right-click the Network icon and select Open Network and Sharing Center. 2. In the left pane, select Change adapter settings. 3. Right-click Wi-Fi and select Properties. 4. Select Internet Protocol Version 4 (TCP/IPv4). 5. Select Properties. 6. Select Obtain an IP address automatically. 7. Select Obtain DNS server address automatically. 8. Select the Alternate Configuration tab to define an alternate configuration for TCP/IP addressing. 9. Select User configured to configure alternate IP settings. 10. Enter the IP address. 11. Enter the subnet mask. 12. Enter the default gateway. 13. Enter the preferred DNS server. 14. Click OK. 15. Click Close. 16. Select the Network icon in the notification area to view the currently connected network.

5.1.8 Configure IP Addresses on Mobile Devices

You work as the IT administrator for a small corporate network. The receptionist, Maggie Brown, uses an iPad to manage employee schedules and messages. Her email settings on the device are configured to communicate with an IMAP mail server over insecure port 143. Maggie also needs to use the new password to connect to the wireless network named CorpNet. In this lab, your task is to complete the following: > Use the Accounts and Passwords option to go to Maggie Brown's email account settings and change the advanced configuration to Use SSL to securely communicate with the IMAP server over server port 993. > Connect Maggie to the CorpNet access point through the Wi-Fi configuration using @CorpNetWeRSecure!& as the password. Complete this lab as follows: 1. Set the email account to use SSL and the secure port 993 as follows: a. Select Settings. b. Select Mail, Contacts, Calendars. c. Select Maggie Brown. d. Select [email protected]. e. Select Advanced. f. Slide the button to enable Use SSL. g. Verify that the server port is set to 993. h. At the top, select Account. i. Click Done. 2. Connect to CorpNet-Wireless Wi-Fi as follows: a. Click Wi-Fi. b. Click CorpNet. c. In the Password field, enter @CorpNetWeRSecure!& as the password. d. Click Join.

5.5.6 Create Host Records

You work as the IT administrator for a small corporate network. You have two servers and a DNS server that use static IP addresses on the 192.168.0.0/24 subnet. You plan to install three more servers soon, so you need to create DNS records for these servers on the CorpDC server. In this lab, your task is to perform the following: > Create an IPv4 Active Directory-integrated primary reverse lookup zone for subnet 192.168.0.0/24. Be sure to accept the default replication and dynamic updates settings. > Create A records and PTR records for the following hosts *If you create the A records before creating the reverse lookup zone, the PTR records will not be created automatically. Complete this lab as follows: 1. Create a primary reverse lookup zone as follows: a. In Hyper-V Manager, select CORPSERVER. b. Right-click CorpDC and select Connect. c. In Server Manager, select Tools > DNS. d. Expand CORPDC. e. Right-click Reverse Lookup Zones and select New Zone. f. Click Next. g. Make sure Primary zone is selected. h. Make sure Store the zone in Active Directory is selected; then click Next. i. Keep the default replication scope setting and click Next. j. Keep the default reverse lookup zone settings and click Next. k. Type 192.168.0 as the network ID. *Omit any trailing zeroes that are excluded based on the subnet mask. For example, type 192.168.1 for subnet 192.168.1.0/24. Type 10.1 for subnet 10.1.0.0/16. l. Click Next. m. Keep the default dynamic update settings; then click Next. n. Click Finish. 2. Create a host (A) and associated pointer (PTR) record as follows: a. In DNS Manager, expand Forward Lookup Zones. b. Right-click CorpNet.com and select New Host (A or AAAA). c. In the Name field, enter the host name. d. In the IP address field, enter the IP address. e. Select Create associated pointer (PTR) record as needed. The reverse lookup zone must exist for this record to be created. f. Click Add Host. g. Click OK. h. Repeat steps 2c through 2g to add additional host records. i. Click Done.

5.1.7 Configure IP Addresses

You work as the IT administrator for a small corporate network. You need to configure the workstation in the Executive Office so it can connect to the local network and the internet. The workstation has two network interface cards. This will allow the workstation to connect to the local network (as shown in the Exhibits) and another small network, which is not yet built. In this lab, your task is to complete the following: > Configure the IP version 4 TCP/IP settings for the network connections using the settings in the table below. > Use the Network and Sharing Center in Windows to confirm that the workstation is properly connected to the small network and the Internet. Complete this lab as follows: > Configure settings for Local Area Connection: - Use 192.168.0.254 for the IP address - Use 255.255.255.0 for the subnet mask - Use 192.168.0.5 for the default gateway - Use 163.128.78.93 or 163.128.80.93 as the preferred DNS server > Configure settings for Local Area Connection 2: - Use 10.0.255.254 for the IP address - Use 255.255.0.0 for the subnet mask - Do not configure a default gateway address - Do not configure a DNS server address 1. In the Notification area, right-click the Network icon. 2. Select Open Network and Sharing Center. 3. To configure the Ethernet adapter, select Ethernet. 4. In the Ethernet Status dialog, select Properties. 5. Select Internet Protocol Version 4 (TCP/IPv4) 6. Select Properties. 7. Make sure that Use the following IP address is selected to manually configure the IP address and default gateway. 8. Enter the required IP address, subnet mask, default gateway, and preferred DNS server address; then select OK. 9. In the Ethernet Properties dialog, select Close. 10. In the Ethernet Status, select Close. 11. Select Change adapter settings to configure the other network adapter. 12. Right-click Ethernet 2 adapter, and click Properties. 13. Repeat steps 5 through 8 to modify the TCP/IP settings for the other network adapter.

5.5.4 Configure DNS Addresses

You're helping a friend in college with his network connection. The dormitory where he lives has installed a 1000BaseT Ethernet network, and this network uses automatic IP addressing with IP address, default gateway, and DNS server information delivered by a DHCP server. You would like to configure your friend's computer (named Dorm-PC) to use a different set of DNS server addresses than the one being delivered by the DHCP server. In this lab, your task is to complete the following: > Configure the IPv4 settings for the Local Area Connection network connection to use the following DNS server addresses: Preferred DNS server: 208.67.222.222 First alternate DNS server: 208.67.222.220 Second alternate DNS server: 208.67.220.123 > Have Dorm-PC validate the static DNS server information. *You must edit the Advanced TCP/IP properties to configure more than two DNS server addresses for the connection. Complete this lab as follows: 1. In the notification area, right-click the Network icon and select Open Network and Sharing Center. 2. Select Ethernet. 3. Select Properties. 4. Select Internet Protocol Version 4 (TCP/IPv4). 5. Select Properties. 6. Select Use the following DNS server addresses to manually configure the DNS server addresses. 7. Select Advanced to configure more than two DNS server addresses. 8. Select the DNS tab. 9. Select Add to configure DNS server addresses. 10. Enter the DNS server address. 11. Select Add. 12. Repeat steps 9-11 to configure additional DNS server addresses. 13. Click OK. 14. Select Validate settings upon exit; then select OK. 15. Click Close to close Ethernet Properties. 16. Click Close to close Ethernet Status.

Which of the following tools would you use to view the MAC addresses associated with IP addresses that the local workstation has contacted recently?

arp Use the arp command to view the MAC addresses associated with IP addresses that the local workstation has contacted recently. When a workstation uses ARP to find the MAC address of an IP address, it places that information in its ARP table. Use the arping command to send an ARP request to a specified IP address. arping works much like ping in that the host with the specified IP address will respond. netstat shows IP-related statistics including incoming and outgoing connections and active sessions, ports, and sockets. nbtstat displays the NetBIOS name tables for both the local computer and remote computers and the NetBIOS name cache.

Consider the following output. ;; res options: init recurs defnam dnsrch ;;got answer: ;;->>HEADER<<-opcode:QUERY, status; NOERROR,id:4 ;;flags: qr rd ra; QUERY:1, ANSWER:1, AUTHORITY:2, ADDITIONAL:0 ;;QUERY SECTION: ;; westsim111.com, type = A, class = IN ;;ANSWER SECTION: westsim111.com. 7h33m IN A 76.141.43.129 ;;AUTHORITY SECTION: westsim111.com. 7h33m IN NS dns1.deriatct111.com. westsim111.com. 7h33m IN NS dns2.deriatct222.com. ;;Total query time: 78 msec ;;FROM: localhost.localdomain to SERVER: default -- 202.64.49.150 ;;WHEN: Tue Feb 16 23:21:24 2005 ;;MSG SIZE sent: 30 rcvd: 103 Which of the following utilities produced this output?

dig The output shown is from the dig command run on a Linux system. Although nslookup and dig provide some of the same information, you can tell this output came from dig because dig produces significantly more detail in its default usage. Use nbtstat to view information on the NetBIOS over TCP/IP (NetBT) name resolutions that have been performed. Use ping to test connectivity between systems on a network.

You need to perform a reverse lookup of the 10.0.0.3 IP address. Which command can you use to accomplish this? (Select two. Each response is a complete solution.)

dig -x 10.0.0.3 nslookup 10.0.0.3 To perform a reverse lookup of the 10.0.0.3 IP address, use either of the above commands: The ipconfig command is used to perform a forward or reverse DNS lookup. The arp 10.0.0.3 command displays the MAC address of the network host with an IP address of 10.0.0.3. The nbtstat -a 10.0.0.3 command displays the NETBIOS name of the host assigned an IP address of 10.0.0.3.

You are troubleshooting a connectivity problem on a Linux server. You are able to connect to another system on the local network, but are not able to connect to a server on a remote network. You suspect that the default gateway information for the system may be configured incorrectly. Which of the following commands would you use to view the default gateway information on the Linux server?

ifconfig Use the ifconfig command on systems running Linux to view information on the TCP/IP configuration of network adapters. Use ipconfig and winipcfg to view network configuration information on Windows systems. Use the dig command on Linux and Unix systems to query Domain Name Service (DNS) servers.

You work in an office that uses Linux servers and Windows servers. The network uses both the TCP/IP protocol. The Linux server is used as an FTP server. Today you have received several calls from people who are unable to contact the Linux server at its known IP address. You are sitting at the Linux server and want to check its IP address. Which command should you use?

ifconfig Use the ifconfig command to show the TCP/IP configuration for a Linux computer.

You need to configure a Cisco RFC 1542-compliant router to forward any received DHCP frames to the appropriate subnet. The address of the remote DHCP server is 172.16.30.1 Which of the following commands would you use to configure the router?

ip helper-address 172.16.30.1 To configure a Cisco router to listen for DHCP traffic and route any received DHCP frames to the appropriate subnet, use the following command: ip helper-address [server_address] The ifconfig command is used on a Linux computer to display TCP/IP configuration information. The host command is used to query the A records of a specified host. The ip address dhcp command is used to configure a Cisco switch to obtain its IP address from a DHCP server.

Which TCP/IP utility gives you the following output?

ipconfig The ipconfig command shows the computer's TCP/IP configuration information. winipcfg also shows the TCP/IP configuration, but in a Windows graphical format.

You have been called in to troubleshoot a connectivity problem on a newly installed Windows Server 2016 system. The system is operating satisfactorily and is able to communicate with other systems on the local network. However it is unable to access any systems on other segments of the corporate network. You suspect that the default gateway parameter for the system has not been configured, or may be configured incorrectly. Which of the following utilities are you most likely to use to view the default gateway information for the system?

ipconfig Use the ipconfig utility to view the TCP/IP configuration of a Windows Server 2003 system. The information displayed by ipconfig includes default gateway information. Use winipcfg to view the TCP/IP configurations on earlier versions of Windows including Windows 98 and Me. It is not supported by Windows Server 2003. Use the ifconfig command to view the TCP/IP configuration on a Linux, Unix or Macintosh system. Use the netstat command to view statistics on TCP connections.

Your office has both Windows and Linux computers. You want to be able to view the address of the default gateway that a computer is using. Which of the following utilities could you use? (Select two.)

ipconfig route Use the ipconfig command on Windows or the route command on Linux to view the default gateway. The ipconfig command will also show the IP configuration for network interfaces, including the IP address, subnet mask, and DNS server addresses being used by a Windows computer. Use host and dig to get the IP address of a host name. Use netstat to view IP-related statistics, including incoming and outgoing connections and active sessions, ports, and sockets.

Examine the following output: Active Connections Proto Local Address Foreign Address State TCP SERVER1:1036 localhost:4832 TIME_WAIT TCP SERVER1:4798 localhost:1032 TIME_WAIT TCP SERVER1:1258 pool-141-150-16-231.mad.east.ttr:24076 CLOSE_WAIT TCP SERVER1:2150 cpe-66-67-225-118.roc.res.rr.com:14100 ESTABLISHED TCP SERVER1:268 C872c-032.cpe.net.cale.rers.com:46360 ESTABLISHED TCP SERVER1:2995 ip68-97-96-186.ok.ok.cox.net:23135 ESTABLISHED Which of the following utilities produced this output?

netstat The output shown is produced by the netstat command. netstat reports the TCP/IP ports open on the local system, as well as identifying the protocol and remote host connected to that port. This information can be very useful when looking for security weaknesses, as a TCP/IP port that is open to traffic unnecessarily represents a security risk. ifconfig is a tool used on Unix, Linux and Macintosh systems to view the configuration of network interfaces, including TCP/IP network settings. The dig command allows you to perform manual DNS lookups from a Linux or Unix system. This can be very useful when troubleshooting name resolution issues. In addition to Linux and Unix systems, nslookup allows you to perform manual DNS lookups from a Windows system.

Your computer is sharing information with a remote computer using the TCP/IP protocol. Suddenly, the connection stops working and appears to hang. Which command can you use to check the connection?

netstat Use the netstat command to check the status of a TCP connection.

Which TCP/IP utility gives you the following output?

netstat -a netstat -a shows you the status of all connections and listening ports.

Which TCP/IP utility gives you the following output?

netstat -r netstat -r shows you the computer's route table.

Which command displays network activity statistics for TCP, UDP, and IP?

netstat -s Netstat -s displays network activity statistics for TCP, UDP, and IP.

netstat

netstat shows the active connections. netstat -a shows detailed information for active connections. netstat -r or route print shows the routing table of the local host. netstat -s shows TCP/IP statistics.

Examine the following output: Server: to.xct.mirrorxhq.net Address: 209.53.4.130 Name: westxsim.com Address: 64.78.193.84 Which of the following utilities produced this output?

nslookup The output is from the nslookup command on a Windows Server system. nslookup is a tool that allows you to send manual DNS resolution requests to a DNS server. The output displays the IP address and host name of the DNS server that performed the resolution, and the IP address and host name of the target specified for resolution. nslookup can be a useful tool when troubleshooting DNS name resolution problems. The ipconfig utility is used on a Windows system to view the TCP/IP configuration of network interfaces. netstat is used to view protocol connections that have been established by the system, as well as what incoming TCP/IP ports are in use by the system. tracert is a tool used to view information on the route a packet takes as it traverses the network to a remote host.

Mary calls to tell you that she can't connect to an intranet server called WebSrv1. From her computer, you ping the server's IP address. The ping test is successful. Which tool would you use on her workstation next to troubleshoot the problem?

nslookup Use nslookup to troubleshoot name resolution problems. Because the ping test was successful, you know that both the client and the server can communicate using TCP/IP with IP addresses. This tells you that the problem is related to name resolution.

You are troubleshooting a network connectivity issue on a Unix system. You are able to connect to remote systems by using their IP address, but unable to connect using the host name. You check the TCP/IP configuration and note that a DNS server IP address is configured. You decide to run some manual resolution queries to ensure that the communication between the Unix system and the DNS server are working correctly. Which utilities can you use to do this? (Choose two.)

nslookup dig The dig and nslookup commands allow you to perform manual DNS lookups from a Linux or Unix system. This can be very useful when you are troubleshooting name resolution issues. Use tracert and traceroute to track the route that a packet takes as it crosses a network. You would not typically use these commands to troubleshoot a name resolution problem, though they may be useful if you are unable to connect to the DNS server.

You work in an office that uses Linux servers and Windows servers. The network uses the TCP/IP protocol. You are sitting at a workstation that uses Windows 10. An application you are using is unable to contact a Windows server named FileSrv2. Which command can you use to determine whether your computer can still contact the server?

ping On a TCP/IP-based network, you can use the ping command to check connectivity between a source and destination computer.

Which TCP/IP utility gives you the following output?

ping The output of the ping command shows you the results of four echo request/reply contacts with a destination host.

Examine the following output. Reply from 64.78.193.84: bytes=32 time=86ms TTL=115 Reply from 64.78.193.84: bytes=32 time=43ms TTL=115 Reply from 64.78.193.84: bytes=32 time=44ms TTL=115 Reply from 64.78.193.84: bytes=32 time=47ms TTL=115 Reply from 64.78.193.84: bytes=32 time=44ms TTL=115 Reply from 64.78.193.84: bytes=32 time=44ms TTL=115 Reply from 64.78.193.84: bytes=32 time=73ms TTL=115 Reply from 64.78.193.84: bytes=32 time=46ms TTL=115 Which of the following utilities produced this output?

ping The output shown was produced by the ping utility. Specifically, the information output was created using theping -t command. The -t switch causes packets to be sent to the remote host continuously until stopped manually. ping is a useful tool for testing connectivity between devices on a network. Using the -t switch with ping can be useful in determining whether the network is congested, as such a condition will cause sporadic failures in the ping stream. tracert is similar to ping in that it tests connectivity between two hosts on the network. The difference is that tracert reports information on all intermediate devices between the host system and the target system. ping, on the other hand, does not report information on intermediate devices. nslookup is a tool provided on Linux, Unix and Windows systems that allows manual name resolution requests to be made to a DNS server. This can be useful when troubleshooting name resolution problems. ifconfig is a tool used on Unix, Linux and Macintosh systems to view the configuration of network interfaces, including TCP/IP network settings.

ping

ping sends an ICMP echo request/reply packet to a remote host. A response from the remote host indicates that both hosts are correctly configured and a connection exists between them.

tcpdump

tcpdump is a packet analyzer that runs in a command line utility. It allows the user to view TCP/IP and other packets as they are transmitted and received over a computer's network.

While working on a Linux server, you are unable to connect to Windows Server 2016 system across the Internet. You are able to ping the default gateway on your own network, so you suspect that the problem lies outside of the local network. Which utility would you use to track the route a packet takes as it crosses the network?

traceroute traceroute is a Linux utility that allows you to track the route of a packet as it traverses the network. The traceroute utility is used on Linux systems, while tracert is used on Windows systems. ipconfig and ifconfig are utilities used to obtain TCP/IP configuration on Windows and Linux systems respectively. nslookup and dig are utilities used to perform manual DNS lookups on Windows and Linux systems respectively.