Chapter 11 Linux

Which is the default subnet mask for address 132.44.156.67?

255.255.0.0

Which file in the Linux system lists all network services including the port assigned to the service?

/etc/services

Which of the following commands would not bring the first Ethernet face down?

/etc/sysconfig/network-scripts /ifcfg-eth0 down

You have a computer that is connected through a NAT router. You want to use a private addressing scheme for your computer. Which of the following IP addresses could you assign a computer?

10.0.12.15 172.18.188.67 192.168.12.253

You are troubleshooting a workstation that is having trouble while browsing the internet. You want to perform some tests on name resolution. Which utility would give you the most information?

dig

Which of the following commands can be used to retrieve the IP address and/or FQDN/hostname information from a DNS server ?

dig host nslookup

Which command displays the IP address and subnet mask values configured on a workstation ?

ifconfig

You are attempting to ping another computer on the internet by its IP address but you are not getting any response. You do however get a response when pinging a host on your own network. Which of the following commands would help you better determine where the problem is?

run traceroute on the IP address of the computer on the internet

Which utility would you use to view current connections and active sessions and ports on a computer?

netstat

Which of the following protocols allows hosts to exchange messages to indicate problems with packet delivery?

ICMP

Which of the following protocols include extensive error checking to ensure that a transmission is sent and received without mistakes?

TCP

You are an application developer and are writing a program to exchange video files through a TCP/IP network. You need to select a transport protocol that will guarantee delivery. Which TCP/IP protocol would you implement that provides this capability?

TCP

Which of the following network protocols must be connected through the internet?

TCP/IP

What port number is used by SNMP?

161

Which of the following is a valid IPv6 address?

FEC0::AB:9007

You are configuring a network firewall to allow STMP outbound e-mail traffic and POP3 inbound e-mail traffic. Which of the following TCP/IP ports should you open on the firewall?

110 25

Which of the following IP addresses is a valid IP address for a host on a public network ?

142.15.6.1

Which port number is used by the IMAP protocol?

143

Which of the following are not valid IP addresses?

148.8.260.7 257.0.122.55 45.22.156.256

Which of the following IP addresses have a default subnet mask of 255.255.0.0?

168.16.5.1 191.168.2.15 129.0.0.1

What is the network address for 199.78.240.240?

199.78.240.0

To transfer files to your company's internal network from home you use FTP. The administrator recently implemented a firewall at the network perimeter and disable as many ports as possible. Now you can no longer make the FTP connection. You suspect that the firewall is causing the issue. Which ports need to remain open so you can transfer the files?

20 21

With a growing concern for security you convince your boss to stop allowing telnet access to the network. Remote connections will now be allowed only through the use of ssh.Which port must you allow through the firewall for ssh access?

22

Which port does telnet use?

23

Which of the following correctly describe the most common format for expressing an IPv6 address?

32 numbers grouped using colons Hexadecimal Numbers

You want to maintain tight security on your internal network so you can restrict access through the network through certain port numbers. If you want to allow users to continue to use the DNS what port should you enable?

53

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

6384:1319:7700:7631:446A:5511:8940:2552 141 : 0:0:0:15:0:0:1

You have just finished configuring a new network card in your Linux system. You would like to verify that it is configured to access the internet. Which of the following solutions would best help you verify that you have internet access?

Attempt to ping a site on the internet

You have a TCP/IP network with 50 hosts. There have been inconsistent communication problems between hosts. You need to 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

Which of the following describes an IPV6 address?

Eight hexadecimal quartets 128-bit address

You are attempting to ping the FQDN of a computer on the internet but are not getting a response. What is the problem?

Pinging the FQDN of a computer does not give you enough information to know what the problem is q

Your computer has an IP address of 161.13.5.15. Your computer is on a :

Public Network

Which of the following commands verifies that TCP/IP is working correctly on a local computer?

ping 127.0.0.1

Which of the following are good reasons to enable NAT?

To translate between Internet IP addresses and the IP addresses on your private network

After arriving at work in the morning you turn on your Linux workstation and attempt to visit an internet news site. After a few minutes, your web browser times out telling you that the website is unavailable. Which of the following troubleshooting steps would be helpful in determining the problem?

Use the ping command to ping the FDQN and IP address of the website you are trying to reach Use the traceroute command to traceroute the FQDN and IP address of the website you are trying to reach

A user calls the helpdesk to report that she is unable to connect to the network after an upgrade of her Linux operating system. You suspect the problem is related to network configuration. Which command would you use to quickly see the current IP address(es) assigned to her computer?

ifconfig -a

Which command would you use to configure the IP address of 192.168.0.123 for the first Ethernet host?

ifconfig eth0 192.168.0.123

You need to temporarily change the IP address of your first Ethernet interface (eth0) to 192.168.1.50 where it is currently set to 10.0.1.50. Which of the following commands would achieve the desired result?

ifconfig eth0 192.168.1.50

You need to set up the IP address for eth1 to 192.168.15.2 with a subnet mask of 255.255255.0. Which command is correct?

ifconfig eth1 192.168.15.2 netmask 255.255.255.0

As you troubleshoot the network connection for your Linux system, you discover the eth1 interface is down. Which command should you use to start the interface?

ifup eth1

The Eth1 interface is currently down. Which command will start the Eth1 interface ?

ifup eth1

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

netstat -s

Which of the following commands would allow you to see if a remote computer is reachable?

ping

Which of the following commands would you use to view your local system's default gateway?

route netstat -r

Which utility is similar to traceroute but does not require elevated privileges?

tracepath

Which command could you use to see a path that a packet traveled across a network to a remote host?

traceroute

While working on a Linux computer you are unable to connect to Windows server 2003 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 a network ?

traceroute