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: dione

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?

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:

auto eth0
iface eth0 inet static
address 192.168.3.4
network 192.168.3.0
netmask 255.255.255.0
gateway 192.168.3.1

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

Answer: gateway 192.168.3.1

What is the hostname of the gateway interface?

Answer: Saturn

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       localhost.localdomain   localhost dione
127.0.1.1       dione

# /etc/hosts -- Hosts file for ICCT Private network
#
# IP            FQDN                            aliases
#
127.0.0.1       localhost.localdomain           localhost myhost
#
192.18.1.1      solaris.icct.co                 solaris inet-gateway
192.18.1.2      venus.icct.com                  venus www
#
#Jupiter cluster
#
192.168.1.3     gw-jupiter.icct.com             gw-jupiter-if1
192.168.2.1     jupiter.icct.com                jupiter jupiter-if2
192.168.2.2     ganymede.jupiter.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              gwsaturn-if1
192.168.3.1     saturn.icct.com                 saturn saturn-if2
192.168.3.2     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
#
# Add other hosts/clusters below here
# (we'll use this to add virtual hosts to the webserver in a later
# lab exercise)

# 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:

saturn.icct.com                 saturn saturn-if2

What is the purpose of the Gateway interface?

Answer:

The purpose of the Gateway interface is to provide a communication bridge between the internet and the networks and to route messages between them.

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=“$” comment=“#”> haneen@dione:~$ route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 192.168.3.0 * 255.255.255.0 U 0 0 0 eth0 link-local * 255.255.0.0 U 1000 0 0 eth0 default saturn.icct.com 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 forwarding .

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

Answer:

 sudo sh -c "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

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 192.168.2.0 netmask 255.255.255.0 gw 192.168.1.3
down route del -net 192.168.2.0 netmask 255.255.255.0 gw 192.168.1.3

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=“$” comment=“#”> icct@dione:~$ netstat -r

#Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface 192.168.3.0 * 255.255.255.0 U 0 0 0 eth0 link-local * 255.255.0.0 U 0 0 0 eth0 default saturn.icct.com 0.0.0.0 UG 0 0 </cli>

netstat (network statistics) is a command-line tool that displays network connections (both incoming and outgoing), routing tables, and a number of network interface statistics.

-r Displays the contents of the kernel routing table.

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

Answer <cli prompt=“$” comment=“#”> icct@dione:~$ 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 8182 0 0 0 7719 0 0 0 BMRU lo 16436 0 29 0 0 0 29 0 0 0 LRU

</cli>

-i : Displays network interfaces and their statistics.

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

Answer <cli prompt=“$” comment=“#”> icct@dione:~$ netstat -ta Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 localhost.localdo:mysql *:* LISTEN tcp 0 0 *:www *:* LISTEN tcp 0 0 *:ssh *:* LISTEN tcp 0 0 localhost.localdoma:ipp *:* LISTEN tcp 0 0 dione.saturn.icct:48717 174.36.133.240-stat:www TIME_WAIT tcp 0 0 dione.saturn.icct:48720 174.36.133.240-stat:www TIME_WAIT tcp6 0 0 [::]:ssh [::]:* LISTEN tcp6 0 0 localhost:ipp [::]:* </cli>

netstat -ta 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=“$” comment=“#”> icct@dione:~$ traceroute mimas traceroute to mimas (192.168.3.3), 30 hops max, 60 byte packets 1 mimas.saturn.icct.com (192.168.3.3) 2.720 ms 2.722 ms 2.716 m </cli>

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

Answer <cli prompt=“$” comment=“#”> icct@dione:~$ traceroute www.swan.ac.uk traceroute to www.swan.ac.uk (137.44.1.7), 30 hops max, 60 byte packets 1 saturn.icct.com (192.168.3.1) 0.259 ms 0.243 ms 0.227 ms 2 * * * 3 * * * 4 * * * 5 * * * 6 * * * 7 * * * 8 * * * 9 * * * 10 * * * 11 * * * 12 * * * 13 * * * 14 * * * 15 * * * 16 * * * 17 * * * 18 * * * 19 * * * 20 * * * 21 * * * 22 * * * 23 * * * 24 * * * 25 * * * 26 * * * 27 * * * 28 * * * 29 * * * 30 * * *

</cli>

Pings have been ignored by the router as traceroute is not forwarding the pings to the other networks leaving 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

#iface eth0 inet dhcp
iface eth0 inet static
address 192.168.10.1
network 192.168.10.0
netmask 255.255.255.0
gateway 192.168.10.1

# route to jupiter-net

up route add -net 192.168.10.0 netmask 255.255.255.0 gw 192.168.10.3
down route del -net 192.168.10.0 netmask 255.255.255.0 gw 192.168.10.3

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

Answer

/etc/hostname

/etc/hosts

/etc/networks/interfaces

/etc/resolv.conf

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

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: — Haneen Al Lawati 2011/12/09 16:18