This wiki page allows you to record the results of your network configuration exercise. You may need to refer to the configuration handout to complete this document.

Answer all questions based on the host that you are configuring in the lab. Edit this wiki page directly to insert your answers. You will probably find this most convenient to do at the same time as you perform the configuration. Where requested, please include listings of the actual configuration files and command outputs directly in the document. Placeholders have been provided for this purpose. Please follow the formatting hints given in the text.

When the exercise is complete you should sign and submit it in for marking. Deadline for completion is the start of the lab on the last week of this term.

This exercise is worth 20% of the module marks.

Which Linux command gives you information about your computer's name on the network?

Answer (delete as appropriate):

hostname 

Use the command selected in Question 1 to determine your host computer's name? What is the name?

Answer:

ganymede

Which configuration file would you need to edit to change your computer's name on the network?

Your answer (one of):

/etc/hostname

Which linux command gives you information on your host's network settings?

Answer one of:

ifconfig 

Use the command selected in Question 4 to complete the following table:

How many hosts can the sub-net defined by your host's netmask support?

Answer one of:

254 

What class of network is the sub-net to which your host has been assigned?

Answer one of:

Class C 

Answer the following questions about your network configuration. Please copy and paste the contents of the files identified in Questions 8 and 11 to your submission.

In which file is the configuration of your Network Interface Controller (NIC) configured?

Answer one of:

/etc/network/interfaces 

Please include a listing of the file chosen in answer to Question 8:

network/interfaces

auto eth0

iface eth0 inet static

address 192.168.2.2

network 192.168.2.0

netmask 255.255.255.0

gateway 192.168.2.1

What is the IP address of the host which serves as the default gateway for your network?

Answer: 192.168.2.1

What is the hostname of the gateway interface?

Answer: jupiter

In which file is the symbolic names of the networks, hosts and interfaces available on the network defined?

Answer one of:

/etc/hosts 
 

Please include a listing of the file chosen in answer to Question 11:

127.0.0.1 ganymede localhost.localdomain localhost 127.0.1.1 icct-desktop

# /etc/hosts – Hosts file for ICCT Private network

#

# IP FQDN aliases

#

127.0.0.1 localhost.localdomain localhost mimas

#

192.168.1.1 solaris.icct.com solaris inet-gateway

192.168.1.2 venus.icct.com venus www

127.0.0.1 localhost.localdomain localhost mimas

#

192.168.1.1 solaris.icct.com solaris inet-gateway

192.168.1.2 venus.icct.com venus www

#

# Jupiter cluster

#

192.168.1.3 gw-jupiter.icct.com gw-jupiter jupiter-if1

192.168.2.1 jupiter.icct.com jupiter jupiter-if2

# Jupiter cluster

#

192.168.1.3 gw-jupiter.icct.com gw-jupiter jupiter-if1

192.168.2.1 jupiter.icct.com jupiter jupiter-if2

192.168.2.2 ganymede.jupiter.icct.com ganymede

192.168.2.3 leda.jupiter.icct.com leda

192.168.2.4 carme.jupiter.icct.com carme

192.168.2.5 arche.jupiter.icct.com arche

#

# Saturn cluster

#

192.168.1.4 gw-saturn.icct.com gw-saturn saturn-if1

192.168.3.1 saturn.icct.com saturn saturn-if2

92.168.3.2 hyperion.saturn.icct.com hyperion

192.168.3.3 mimas.saturn.icct.com mimas

192.168.3.4 dione.saturn.icct.com dione

192.168.3.5 titan.saturn.icct.com titan

192.168.3.8 tethys.saturn.icct.com tethys

#

# The following lines are desirable for IPv6 capable hosts ::1 localhost ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters ff02::3 ip6-allhosts

What is the symbolic name of your network's gateway interface?

Answer: jupiter.icct.com jupiter jupiter-if2

What is the purpose of the Gateway interface?

Answer: A gateway interface allows two or more computers to use the Internet at the same time. While doing so, only the gateway's IP address will be visible on the Internet. The rest of the computers will be “hidden” behind the gateway. This is called IP masquerading.

Which linux command shows the routing table for your host?

Answer: route

Run the command identified in Question 14 and reproduce its output here.

Answer

<cli prompt=“$” comment=“#”>

icct@ganymede:~$ route #kernel ip routing table Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface jupiter-net * 255.255.255.0 U 0 0 0 eth0 169.254.0.0 * 255.255.0.0 U 1000 0 0 eth0 default jupiter.icct.co 0.0.0.0 UG 100 0 0 eth0

</cli>

How many interfaces (NICs) must a router have?

Answer one of:

2

Which system feature must be turned on if you want a Linux host to act as a router?

Answer: Enable ip forwarding

Which run-time command can be used to make a Ubuntu Linux host act as a router?

Answer: echo 1 > /proc/sys/net/ipv4/ip_forward

In which file is the setting defined in Question 17 set if you want a Ubuntu host to be configured as a router at boot-time?

Answer:

/etc/network/options and change the line ip_forward=no to ip_forward=yes

Reproduce the contents of the file defined in Question 17 to make a Ubuntu host into a router?

Answer

ip_forward=yes 

What setting has been added to the network configuration file to define a route to icct-net from your sub-network's cluster-server?

Answer:

up route add -net 192.168.3.0 netmask 255.255.255.0 gw 192.168.1.4

down route del -net 192.168.3.0 netmask 255.255.255.0 gw 192.168.1.4

The Linux command netstat gives a lot of useful information on your network. In the following 3 questions, reproduce the output of various usages of netstat. You should annotate your results with a brief explanation of what they mean. You may need to print the output and attach to the submission.

Give and explain the output of the command netstat -r.

Answer <cli prompt=“$” comment=“#”> icct@ganymede:~$ netstat -r Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface jupiter-net * 255.255.255.0 U 0 0 0 eth0 169.254.0.0 * 255.255.0.0 U 0 0 0 eth0 default jupiter.icct.co 0.0.0.0 UG 0 0 0 eth0

</cli>

Add your explanation here.

netstat -r displays the kernel routing table

Give and explain the output of the command netstat -i.

Answer <cli prompt=“$” comment=“#”> icct@ganymede:~$ netstat -i Kernel Interface table Iface MTU Met RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR Flg eth0 1500 0 7220 0 0 0 5276 0 0 0 BMRU lo 16436 0 12 0 0 0 12 0 0 0 LRU . </cli>

Add your explanation here.

netstat -i displays a table of all network interfaces.

Give and explain the output of the command netstat -ta.

Answer <cli prompt=“$” comment=“#”> icct@ganymede:~$ netstat -ta Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 ganymede:mysql *:* LISTEN tcp 0 0 *:www *:* LISTEN tcp 0 0 *:ssh *:* LISTEN tcp 0 0 ganymede:ipp *:* LISTEN tcp 0 0 ganymede.jupiter.:36541 174.36.133.240-stat:www TIME_WAIT tcp 0 0 ganymede.jupiter.:36538 174.36.133.240-stat:www TIME_WAIT tcp6 0 0 [::]:ssh [::]:* LISTEN tcp6 0 0 localhost:ipp [::]:* LISTEN </cli>

Add your explanation here.

shows all active internet connections and their current state.

Install, if necessary, the traceroute command then answer the following two questions.

Give the output of traceroute from your host to any host on one of the other ICCT networks.

Answer <cli prompt=“$” comment=“#”> icct@ganymede:~$ traceroute mimas traceroute to mimas (127.0.0.1), 30 hops max, 60 byte packets 1 ganymede (127.0.0.1) 0.017 ms 0.004 ms 0.004 ms

</cli>

Give the output of traceroute from your host to www.swan.ac.uk

Answer <cli prompt=“$” comment=“#”> icct@ganymede:~$ traceroute www.swan.ac.uk traceroute to www.swan.ac.uk (137.44.1.7), 30 hops max, 60 byte packets 1 jupiter.icct.com (192.168.2.1) 0.539 ms 0.533 ms 0.527 ms 2 * * * 3 * * * 4 * * * 5 * * * 6 * * * 7 * * * 8 * * * 9 * * * 10 * * * 11 * * * 12 * * * 13 * * * 14 * * * 15 * * *

</cli>

Explain the result.

traceroute is not forwarding the pings to the corresponding network,thereby leaves a dead connection.

A new sub-network engineering-net (192.168.10.0/24) is to be added to the ICCT network. Host engineering (192.168.10.1/32) is a cluster server for this new network. Give the settings needed to set up this host as a router to icct-net, jupiter-net, and saturn-net and a gateway for engineering-net.

Answer

For all of the computer we have to edit the /etc/hosts and add;

192.168.10.1 engineering.swan-icct.ac.uk gw-engineering engineering-if2

If there are some clients in the engineering network we have to define them also.

Which other files would you need to modify to correctly set up this new router?

Answer

/etc/hosts

/etc/networks

/etc/network/interfaces

/etc/network/options

Summarize the changes that you would you need to make to your host's network configuration to have the new engineering sub-network recognized?

Answer

address 192.168.1.4

network 192.168.1.0

netmask 255.255.255.0

gateway 192.168.1.1

# route to jupiter-net

up route add -net 192.168.2.0 netmask 255.255.255.0 gw 192.168.1.3

down ro/etc/network/interfacesute del -net 192.168.2.0 netmask 255.255.255.0 gw 192.168.1.3

Which other files would you need to modify to fully configure your host to recognizes the new engineering sub-network?

Answer

/etc/resolve.conf

/etc/hosts

/etc/nsswitch.conf

/etc/network/interfaces

I hereby submit this work for marking.

Your signature here: — emmanuel 2011/12/08 08:57