ICND 1 B

Identify three valid host addresses in any subnet of the 201.168.27.0 network, assuming a fixed subnet mask of 255.255.255.240. (Choose three.) A.201.168.27.33 B.201.168.27.112 C.201.168.27.119 D.201.168.27.126 E.201.168.27.175 F.201.168.27.208

A, C, D. A subnet mask of 255.255.255.240 divides the fourth octet into subnet parts: the highest four bits and a host part (the lowest four bits). You simply check the fourth octet to ensure that all subnet and host parts are okay. The host bit portion cannot be 0000 or 1111. Answers A, C, and D are correct because 33 in decimal is 00100001, 119 in decimal is 01110111, and 126 in decimal is 01111110. Answer B is incorrect, as 112 in decimal is 1110000 in binary. This is not a valid host address in this network. All its host bits are zero. Answer E is incorrect, as 175 in decimal is 10101111 in binary. All host bits are ones. This is the local broadcast address and cannot be used as a host address. Answer F is incorrect, as 208 in decimal is 11010000 in binary. This is not a valid host address in this network, and all its host bits are zero.

RFC 1918 defines the private IP address ranges. Which of the following IP addresses are considered part of these ranges? (Choose three.) A.10.23.45.67 B.126.21.34.56 C.172.16.32.1 D.172.31.234.55 E.192.169.4.5

A, C, D. These addresses are all part of the private ranges of 10.x.x.x and 172.16.x.x-172.31.x.x. Answer B is incorrect, as it does not fall into any of the RFC 1918-specified private ranges. Instead, it is a public IP address that is routable on the Internet. Answer E is incorrect, as it is not a part of the private IP address range. It falls outside the 192.168.x.x range and thus is a public IP address.

Which of the following represent a private IP address? (Choose two.) A.192.168.5.205 B.172.32.65.31 C.10.168.5.205 D.224.16.23.1

A, C. The private address ranges are 10.x.x.x, 172.16.x.x-172.31.x.x, and 192.168.x.x. Answers B and D fall outside these ranges.

You have an internal web server that has the IP address 172.16.5.9. You need to enable this server to be accessed on TCP port 80 from the Internet; what would be the best solution for this situation? A.Static NAT B.Dynamic NAT C.NAT Overload D.Standard Routing E.Port NAT

A. Static NAT provides the best solution when you need a 1:1 translation from a private address or port number to a public address or port number. Answer B is incorrect because Dynamic NAT allows many hosts to be translated at the same time. Answer C is incorrect because NAT Overload allows many internal hosts to share a single Internet IP address. Answer D is also incorrect. Standard routing does not work because private addresses are blocked from traversing the Internet. Finally, Answer E is incorrect because there is no such thing as Port NAT.

You are a network technician at Acme, Inc. You have subnetted the 192.168.72.0 network with a /30 mask for connections between your routers. Your boss asks you how many usable subnetworks and usable host addresses per subnet this will provide. What should you tell her, assuming your router can use all possible subnets? A.64 networks and 2 hosts B.8 networks and 30 hosts C.8 networks and 32 hosts D.16 networks and 16 hosts E.16 networks and 14 hosts

A. The mask /30 gives you 64 subnetworks using the (2n) formula, where n equals the number of bits borrowed for the subnet. You also find that there are two available hosts per subnet using the (2n − 2) formula, where n equals the number of bits borrowed for the hosts. Because all subnets are usable, you do not need to subtract 2 from the subnetworks. Answer B is incorrect, as that would be a /27 mask. Answer C is incorrect, as there would never be 32 hosts per subnet; you always have to subtract 2 from the 2n formula because of the network ID and the directed broadcast address on each subnetwork. Answer D is incorrect, as you would never have 16 hosts per subnet; you always have to subtract 2 from the 2n formula because of the network ID and the directed broadcast address on each subnetwork. Answer E is incorrect, as the /28 subnet mask gives you 16 subnetworks and 14 possible hosts.

You are configuring a subnet for the Acme, Inc., branch office in Beijing. You need to assign IP addresses to hosts in this subnet. You have been given the subnet mask of 255.255.255.224. Which of these IP addresses would be valid? (Choose three.) A.15.234.118.63 B.92.11.178.93 C.134.178.18.56 D.192.168.16.87 E.201.45.116.159 F.217.63.12.192

B, C, and D. These three are valid host addresses when using a 255.255.255.224 subnet mask against the address. Answer A is incorrect, as it is a broadcast address on the 16.234.118.32 network. Answer E is incorrect, as it is a broadcast address on the 210.45.116.128 network. Answer F is incorrect, as it is the network address for 237.63.12.192.

What two statements describe the IP address 172.16.3.68/23? (Choose two.) A.It is from the subnet 172.16.3.0 255.255.254.0. B.The broadcast address of the subnet is 172.16.3.255. C.The broadcast address of the subnet is 172.16.4.255. D.The first valid IP address of the subnet is 172.16.2.1. E.The last valid IP address of the subnet is 172.16.4.254.

B, D. By reverse-engineering the subnet mask, you can find the original network range for this address as 172.16.2.0 to 172.16.3.255. Because the first and last addresses in the range are reserved, the first usable address becomes 172.16.2.1, and the last usable address becomes 172.16.3.254. Answer A is incorrect because this address is from the 172.16.2.0 255.255.254.0 subnet. Answer C is incorrect because the broadcast address is 172.16.3.255. Answer E is incorrect because the last valid address for the subnet is 172.16.3.254.

Which of the following are true of the DHCP Discover message? (Choose two.) A.It uses TCP as the transport layer protocol. B.It uses UDP as the transport layer protocol. C.It uses a reserved multicast MAC address. D.It uses a unicast data link and network layer address to reach the DHCP server. E.It uses a destination MAC address of FFFF.FFFF.FFFF. F.It is commonly ignored and discarded by the DHCP server.

B, E. The DHCP Discover message is a broadcast packet generated by a DHCP client when attempting to obtain an IP address. Every broadcast message that uses the IP protocol suite will use UDP as a transport layer protocol (because TCP requires a three-way handshake to establish communication, making answer A incorrect). Likewise, broadcast messages are always sent to the destination MAC address FFFF.FFFF.FFFF (or FF-FF-FF-FF-FF-FF, depending on the format you are more familiar with). This forces the Layer 2 switch to send the message out all ports. Answers C and D are incorrect because DHCP Discover packets use broadcast rather than multicast or unicast to communicate. Answer F is incorrect because DHCP servers process and respond to DHCP Discover packets.

Which of the following protocols use both TCP and UDP ports? A.HTTP B.DNS C.FTP D.Telnet E.TFTP

B. DNS uses both TCP and UDP port 53. The TCP form of DNS is typically used to replicate domain records between DNS servers. The UDP form of DNS is typically used for domain lookups from network clients. Answers A, C, D, and E are incorrect because HTTP uses TCP port 80, FTP uses TCP port 21, Telnet uses TCP port 23, and TFTP uses UDP port 69.

What two statements describe the IP address 12.51.5.65/23? (Choose two.) A.It is a private IP address. B.The subnet address is 12.51.5.0 255.255.254.0. C.The last usable host address is 12.51.5.254. D.The lowest usable host address is 12.51.4.1. E.The range of usable addresses is from 12.51.5.1 to 12.51.5.254.

C, D. Given the 12.51.5.65/23 address, you can work backward to find the network range as 12.51.4.0 to 12.51.5.255 (which makes answer E incorrect). The first usable address from this range is 12.51.4.1 and the last is 12.51.5.254. Answer B is incorrect because the subnet address is 12.51.4.0/23. Answer A is incorrect because the 12.0.0.0/8 network is considered public addressing space.

What two statements accurately describe private IP addresses? (Choose two.) A.Addresses that are nonroutable B.Addresses that are assigned to an organization by the IANA C.Addresses that cannot be routed on the Internet D.An addressing scheme devised to conserve the public IP address space E.Addresses that begin with 169.253.0.0/16

C, D. Private IP addresses are prevented from routing on the Internet because they are duplicated in organizations around the world. The private addressing scheme was designed to be used with NAT to provide Internet access while conserving public address space. Answer A is incorrect because private IP addresses are able to route; they are just unable to route on the Internet. Answer B is incorrect because the Internet Assigned Numbers Authority (IANA) handles public IP address assignments rather than private IP address assignments. Answer E is incorrect because addresses that begin with 169.253.0.0/16 are perfectly valid, public addresses. The range 169.254.0.0/16 is considered the auto-configured IP address range (which is non-routable).

You are designing a network that needs to support 55 users. You don't plan to extend the segment beyond the current number of users. Which subnet mask would best meet your needs? A.255.255.0.0 B.255.255.255.0 C.255.255.255.192 D.255.255.255.160

C. This particular subnet mask allows for up to 62 hosts per network. Answer A is incorrect, as it allows for 65,534 hosts. Answer B is incorrect, as it allows up to 254 hosts. Answer D is incorrect, as it is not a valid subnet mask.

What form of NAT maps multiple private IP addresses to a single public address by using different port numbers? A.Static NAT B.Dynamic NAT C.Port NAT D.Overload E.Port load

D. NAT Overload allows multiple private addresses to share a single public address by using unique source port numbers for each request. Answer A is incorrect because Static NAT provides a 1:1 mapping between public and private IP addresses. Answer B is incorrect because Dynamic NAT translates one pool of addresses to another, also in 1:1 fashion. Answers C and E are incorrect because there is no such thing as Port NAT or Port load.

You give your IT department a spreadsheet of IP addresses and their subnets. You receive a call from one of the junior techs asking what the /26 means next to the IP addresses. You tell her: A.It represents the number of hosts possible on that subnetwork. B.It represents the number of subnetworks being used. C.It represents the class of IP address being used. D.It represents the number of bits in the subnet mask that are set to 1.

D. Prefix notation, or / notation, shows the number of subnet mask bits that are turned to one, signifying a network portion of the address. Answer A is incorrect, as it does not show the number of hosts on a subnetwork. Answer B is incorrect, as it does not show the number of subnetworks in use. Answer C is incorrect because, even though you can figure out whether it is a Class A, B, or C address based on the prefixes of /8, /16, or /24, it does not necessarily show the class of the address.

You have added a new switch to your network. You want to manage it remotely, so you need to assign it an IP address. Your router that connects to the switch has an IP address of 172.16.12.33/27. Which of the following addresses can you assign to this switch? A.172.16.12.33/28 B.172.16.12.32/27 C.172.16.12.33/27 D.172.16.12.34/27 E.172.16.12.35/28 F.172.16.12.38/28 G.172.16.12.63/27

D. The next valid IP host address in the 172.16.12.32 network is 172.16.12.34. Answer A is incorrect, as it is on a different subnetwork with a /28 mask. Answer B is incorrect, as it is the network address for that particular subnetwork. Answer C is incorrect, as it is the same IP address as the router interface. Answers E and F are incorrect as well, as they are on different subnets than the router interface. Answer G is incorrect because it represents the broadcast address for the 172.16.12.32 subnetwork and cannot be used as a host address.

Based on the following output, what form of NAT is being used on this router? Pro Inside global Inside local Outside local Outside global tcp 71.209.254.131:1433 192.168.1.25:1433 64.12.189.217:443 64.12.189.217:443 tcp 71.209.254.131:1434 192.168.1.25:1434 205.188.8.237:443 205.188.8.237:443 tcp 71.209.254.131:1435 192.168.1.25:1435 205.188.248.168:443 205.188.248.168:443 tcp 71.209.254.131:1436 192.168.1.25:1436 207.200.94.66:80 207.200.94.66:80 tcp 71.209.254.131:1437 192.168.1.25:1437 205.188.216.1:80 205.188.216.1:80 tcp 71.209.254.131:1438 192.168.1.25:1438 207.200.94.66:80 207.200.94.66:80 tcp 71.209.254.131:1440 192.168.1.25:1440 64.12.174.185:80 64.12.174.185:80 tcp 71.209.254.131:1442 192.168.1.25:1442 207.200.74.12:80 207.200.74.12:80 tcp 71.209.254.131:1443 192.168.1.25:1443 64.12.187.25:80 64.12.187.25:80 tcp 71.209.254.131:1444 192.168.1.25:1444 207.200.74.66:80 207.200.74.66:80 tcp 71.209.254.131:1445 192.168.1.25:1445 209.62.180.90:80 209.62.180.90:80 tcp 71.209.254.131:1446 192.168.1.25:1446 8.7.28.81:80 8.7.28.81:80 tcp 71.209.254.131:1447 192.168.1.25:1447 209.62.180.90:80 209.62.180.90:80 tcp 71.209.254.131:52811 192.168.1.26:52811 205.240.85.61:80 205.240.85.61:80 tcp 71.209.254.131:52813 192.168.1.26:52813 205.240.85.61:80 205.240.85.61:80 udp 71.209.254.131:1035 192.168.1.225:1035 63.236.1.135:53 63.236.1.135:53 udp 71.209.254.131:1035 192.168.1.225:1035 64.236.1.107:53 64.236.1.107:53 A.Static NAT B.Port-based NAT C.Dynamic NAT D.NAT Overload

D. The output is demonstrating NAT Overload because it shows many Inside Local (internal) IP addresses being translated to a single Inside Global (external) IP address using unique source port numbers. Answer A is incorrect because Static NAT would show 1:1 mappings between Inside Local and Inside Global IP addresses. Answer B is incorrect because there is no such thing as port-based NAT. Answer C is incorrect because Dynamic NAT would also show many 1:1 mappings between pools of IP addresses.

You are designing an IP address scheme for your brand-new remote office. The vice president of IT calls to tell you that you will be in charge of the 192.168.1.64/26 subnetwork. This supplies you with a single subnetwork with 62 hosts. You need to have at least two subnets with 14 hosts in each subnet. What custom subnet mask should you use? A.255.255.255.128 B.255.255.255.192 C.255.255.255.224 D.255.255.255.240 E.255.255.255.248

D. The subnet mask 255.255.255.240 gives you two additional subnets, with up to 14 hosts per subnetwork. Answer A is incorrect, as it is a higher subnet mask than your original /26, which is actually called supernetting. Answer B is incorrect because it is your original subnet mask. Answer C is incorrect, as it does not give you enough subnets. Answer E is incorrect, as it gives you enough subnets (six), but you would have only six hosts per network.

You have recently changed configuration settings on your DHCP server and network infrastructure. Some of the DHCP clients no longer have access to network resources. What would be the best option to troubleshoot this issue? A.Reboot the DHCP server. B.Use the tracert command to determine the location of the network outage. C.Verify the ARP cache on the clients by using the arp -a command. D.Issue the ipconfig /release followed by the ipconfig /renew commands from a command prompt.

D. When making changes to an IP scope on a DHCP server, you may need to release and renew IP addresses on the network clients. This will allow them to get any new scope options that were implemented, such as new IP addresses, DNS server settings, or a default gateway. Answer A is incorrect because DHCP servers should not have to be rebooted anytime configuration settings are changed. Answer B is incorrect because tracert is typically used to find router issues in a communication path. Answer C is incorrect because DHCP server settings should not affect the client's ARP cache. As a side note, the ARP cache will be cleared on releasing and renewing an IP address.

An administrator pings the IP address 127.0.0.1 from a command prompt on a server. If he receives reply messages, what does this indicate? A.The server has connected successfully to a device using IP. B.The server has connectivity with local devices. C.The server can reach the Internet. D.TCP and UDP operations are working successfully. E.TCP/IP is operating on the server.

E. 127.0.0.1 is a reserved loopback address for testing connectivity to the local device (in this case, the server). Being able to successfully ping the loopback address does not indicate any connectivity capabilities outside the local system, making answers A, B, and C incorrect. Answer D is incorrect because pinging a local loopback address tests the ICMP protocol rather than TCP or UDP.

How many valid host addresses are provided in the 10.55.128.0/22 subnet? A.254 B.255 C.510 D.512 E.1022

E. The formula used to calculate the maximum number of hosts per subnet is (2^x) − 2, where "x" is the number of host bits in the subnet mask. A /22 subnet mask has 10 host bits, so (2^10) − 2 = 1022. Keep in mind that you will not have access to a calculator on any Cisco exam, so it may be beneficial to become familiar with common exponential values. All other answers do not apply to this question.

You need to assign the IP address 192.168.6.1/23 to the FastEthernet0/0 interface of your router. Place the numbers of the following commands in the correct order below. NOTE: Not all commands will be used. You are currently at the following prompt: Router> 1 = config memory 2 = int fa0/0 3 = configure terminal 4 = enable 5 = fastethernet 0/0 6 = ip 192.168.6.1 255.255.254.0 7 = ip address 192.168.6.1 /23 8 = ip address 192.168.6.1 255.255.254.0 A.______ B.______ C.______ D.______

The correct order of the commands is as follows: a.___4__ b.___3__ c.___2__ d.___8__