Network+ Chapter 3: Addressing on Networks

What decimal number corresponds to the binary number 1111 1111? A. 255 B. 256 C. 127 D. 11,111,111

- A. 255 - IPv4 ADDRESSES The largest possible 8-bit number is 1111 1111, which is equal to 255 in decimal. Each of the 4 octets can be any number from 0 to 255.

If you are connected to a network that uses DHCP, and you need to terminate your Windows workstation's DHCP lease, which command would you use? A. ipconfig /release B. ipconfig /renew C. ifconfig /release D. ifconfig /renew

- A. ipconfig /release - ipconfig /release , releases the IP address when dynamic IP addressing is being used. Releasing the IP address effectively disables the computer's communications with the network until a new IP address is assigned.

How many bits does an IPv6 address contain?

- Addressing Overview, IPv6 (Internet Protocol version 6) addresses have 128 bits and are written as eight blocks of hexadecimal numbers.

Suppose you send data to the 11111111 11111111 11111111 11111111 IP address on an IPv4 network. To which device(s) are you transmitting? A. All devices on the Internet B. All devices on your local network C. The one device that is configured with this IP address D. No devices

- B. All devices on your local network - Reserved IP addresses 255.255.255.255 == 11111111 11111111 11111111 11111111, used for broadcast messages by TCP/IP background processes. A broadcast message is read by every node on the network.

You have just set up a new wireless network at your house, and you want to determine whether your Linux laptop has connected to it and obtained a valid IP address. What command will give you the information you need?

- ifconfig -a , displays the TCP/IP information associated with every interface on a Linux device, can be used with other parameters.

Which computers are the highest authorities in the Domain Name System hierarchy? A. Authoritative name servers B. Root servers C. Top-level domain servers D. Primary DNS servers

- B. Root servers - Name Servers, DNS name servers are organized in a hierarchical structure. At the root level root servers hold information used to located the TLD (top-level domain) servers.

What type of device does a computer turn to when attempting to make contact with a host with a known IP address on another network? A. Default Gateway B. DNS server C. Root server D. DHCP server

- A. Default Gateway - IP ADDRESSES, The Default Gateway is the gateway device that nodes on the network turn to first for access to the outside world.

You are the network manager for a computer training center that allows students to bring their own laptops to class for learning and taking notes. Students need access to the Internet, so you have configured your network's DHCP server to issue IP addresses automatically. Which DHCP options should you modify to make sure you are not wasting addresses used by students who have left for the day?

- DHCP Issues, a DHCP server gives a client an IP address, it sets a time limit, or lease time, on the IP address. By default, this time limit is usually anywhere from 120 minutes to 8 days, depending on the device and software used.

When running a scan on your computer, you find that a session has been established with a host at the address 208.85.40.44:80. Which application layer protocol is in use for this session? What command-line utility might you use to determine which computer is the host?

- Port 80, :80 is the HTTP process from the Well-known TCP and UDP ports. nslookup remains the best way to resolve DNS issues.

You have just brought online a new secondary DNS server and notice your network-monitoring software reports a significant increase in network traffic. Which two hosts on your network are likely to be causing the increased traffic and why? A. The caching and primary DNS servers, because the caching server is requesting zone transfers from the primary server B. The secondary and primary DNS servers, because the secondary server is requesting zone transfers from the primary server C. The root and primary DNS servers, because the primary server is requesting zone transfers from the primary DNS server D. The web server and primary DNS server, because the web server is requesting zone transfers from the primary DNS server

- B. The secondary and primary DNS servers, because the secondary server is requesting zone transfers from the primary server.

Which of these commands is available only in Linux? A. ping B. ipconfig C. dig D. nslookup

- C. dig - Trouble Shooting Tools, Some of the most helpful tools are ping, ipconfig (Windows only), ifconfig (Linux only), nslookup, and dig (Linux only). The dig (domain information groper) utility is available on Linux and macOS and provides more detailed domain information than nslookup.

Which part of a MAC address is unique to each manufacturer? A. The network identifier B. The OUI C. The device identifier D. The physical address

- B. The OUI - MAC ADDRESSES, The first 24 bits are known as the OUI (Organizationally Unique Identifier), which identifies the NIC's manufacturer. A manufacturers OUI is assigned by the IEEE.

Which type of DNS record identifies an email server? A. AAAA record B. CNAME record C. MX record D. PTR record

- C. MX record - Resource Records in a DNS database, MX (mail exchanger) record, identifies an email server and is used for email traffic.

When your computer first joins an IPv6 network, what is the prefix of the IPv6 address the computer first configures for itself? A. FF00::/8 B. 2001::/64 C. 2001::/3 D. FE80::/10

- D. FE80::/10 - Link Local Address can be used for communicating with nodes in the same link, and is similar to an autoconfigured APIPA address in IPv4. It begins with FE80::/10. The first 10 bits of the reserved prefix are fixed (1111 1110 10), and the remaining 54 bits in the 64 bit prefix are all zeroes.

While troubleshooting a network connection problem for a coworker, you discover the computer is querying a nonexistent DNS server. What command-line utility can you use to assign the correct DNS server IP address?

- NSLOOKUP, nslookup utility allows you to query the DNS database from any computer on the network and find the host name of a device by specifying its IP address, or visa versa. This is useful for verifying that a host is configured correctly or for troubleshooting DNS resolution problems.

You issue a transmission from your workstation to the following socket on your LAN: 10.1.1.145:110. Assuming your network uses standard port designations, what application layer protocol handles your transmission?

- Port 110 or :110 from the IP address indicates from the Well-known TCP and UDP ports as being POP3 using TCP, incoming email messages (downloaded messages)

Suppose you want to change the default port for RDP as a security precaution. What port does RDP use by default, and from what range of numbers should you select a private port number?

- RDP uses Port 3389 from the Well-known TCP and UDP ports. Dynamic and Private Ports range from 49152 to 65535 and are open for use without restriction

What is the range of addresses that might be assigned by APIPA?

- Reserved IP addresses, 169.254.0.1 through 169.254.255.254, used to create an APIPA (Automatic Private IP Addressing) address when a computer configured for DHCP first connects to the network and is unable to lease an IPv4 address from the DHCP server.

You have decided to use a SNAT and PAT on your small office network. At minimum, how many IP addresses must you obtain from your ISP for all five clients in your office to be able to access servers on the Internet?

- Using SNAT (Static Network Address Translation or Source Network Address Translation), the gateway assigns the same public IP address to a host each time it makes a request to access the Internet. Small home networks with only a single public IP address provided by its ISP use SNAT.

FTP sometimes uses a random port for data transfer, but an FTP server always, unless programmed otherwise, listens to the same port for session requests from clients. What port does an FTP server listen on?

- Well-known TCP and UDP ports - Port 21 FTP using TCP, file transfer-control (an FTP server listens at port 21 and sends/receives data at port 20)