Chapter 3: Addressing on Networks

What decimal number corresponds to the binary number 11111111?

255

Which type of DNS record identifies an email server?

MX record

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 in interactive mode

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

Which part of a MAC address is unique to each manufacturer?

The OUI

How many bits does an IPv6 address contain?

128

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 option should you modify to make sure you are not wasting addresses used by students who have left for the day?

DHCP lease time

When your computer first joins an IPv6 network, what is the prefix of the IPv6 address the computer first configures for itself ?

FE80::/10

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 is normally assigned port 3389. If you want increased security, any port assigned from 49152 to 65535 should be ok.

Which computers are the highest authorities in the Domain Name System hierarchy?

Root servers

Which of these commands is available only in Linux?

dig

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?

ipconfig /release

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

169.254.0.1 through 169.254.255.254

Suppose you send data to the 11111111 11111111 11111111 11111111 IP address on an IPv4 network. To which device(s) are you transmitting?

All devices on your local network

What type of device does a computer turn to first when attempting to make contact with a host with a known IP address on another network?

Default gateway

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?

HTTP, nslookup

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

One

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?

POP3 (Post Office Protocol 3)

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?

Port 21

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?

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