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: Leda

Hostnames should use lower-case names

— Chris Jobling 2012/12/06 09:13

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: <cli prompt=“$” comment=“$”> auto eth0 iface eth0 inet static

address 192.168.2.22
network 192.168.2.0
netmask 255.255.255.0
gateway 192.168.2.1

</cli>

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: <cli prompt=“$” comment=“$”> # /etc/hosts – Hosts file for ICCT Private network # # IP FQDN aliases # 127.0.0.1 localhost.localdomain localhost myhost # 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-planets jupiter-if1 192.168.2.1 jupiter.icct.com jupiter jupiter-if2 192.168.2.23 carme.jupiter.icct.com carme guo 192.168.2.22 leda.jupiter.icct.com leda jumana 192.168.3.35 titan.saturn.icct.com titan ali 192.168.3.69 mimas.saturn.icct.com mimas richard 192.168.3.3 tethys.saturn.icct.com tethys jenna 192.168.3.2 dione.saturn.icct.com dione gary 192.168.3.21 hyperion.saturn.icct.com hyperion megan # # Saturn cluster

192.168.1.4 gw-saturn.icct.com gw-saturn saturn-if1 192.168.3.1 saturn.icct.com saturn saturn-if2 # # Add other hosts/clusters below here # (we'll use this to add virtual hosts to the web-server in a later # lab exercise)

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

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

Answer:

jupiter.icct.com

What is the purpose of the Gateway interface?

Answer:

The gateway interface is a standard way for a Web server to pass a Web user's request to an application program and to receive data back to forward to the user i.e. it is the a door to the rest of the internet. It provides a consistent way for data to be passed from the user's request to the application program and back to the user. This means that the person who writes the application program can makes sure it gets used no matter which operating system the server uses.

Nope! Your definition is for the Common Gateway Interface (CGI) which is use in web servers. In this context the gateway connects an IP network to another network for the purpose of packet routing

— Chris Jobling 2012/12/06 09:14

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

<cli prompt=“$” comment=“$”> icct@leda:~$ ssh jupiter icct@jupiter:~$ nano /etc/network/options </cli>

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

Answer <cli prompt=“$” comment=“$”> ip_forward=yes spoofprotect=yes syncookies=no </cli>

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: <cli prompt=“$” comment=“$”> up route add -net 192.168.2.0 netmask 255.255.255.0 gw 192.168.1.4

# This file describes the network interfaces available on your system # and how to activate them. For more information, see interfaces(5).

# This is Jupiter

# The loopback network interface auto lo iface lo inet loopback

# The primary network interface auto eth0 iface eth0 inet static

address 192.168.1.3
network 192.168.1.0
netmask 255.255.255.0
gateway 192.168.1.1
# route to saturn-net
up    route add -net 192.168.2.0 netmask 255.255.255.0 gw 192.168.1.4
down  route del -net 192.168.2.0 netmask 255.255.255.0 gw 192.168.1.4

auto eth0 iface eth0 inet static

address 192.168.2.22
network 192.168.2.0
netmask 255.255.255.0
gateway 192.168.2.1

#iface eth0 inet dhcp #iface eth1 inet dhcp

# Uncomment following lines to active third interface #auto eth2 #iface eth2 inet dhcp </cli>

Definition of second network interface looks wrong. It should be eth1 and the IP address is 192.168.2.1 for jupiter. Did you actually copy the interfaces file from jupiter?

— Chris Jobling 2012/12/06 09:18

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=“$” comment=“$”> Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface saturn-net saturn.swan-icc 255.255.255.0 UG 0 0 0 eth0 jupiter-net * 255.255.255.0 U 0 0 0 eth1 icct-net * 255.255.255.0 U 0 0 0 eth0 default solaris.swan-ic 0.0.0.0 UG 0 0 0 eth0 </cli>

Add your explanation here:

The command 'netstat -r' shows the kernel routing information by displaying the kernel routing table. This table includes all the information in divided columns arranged according to: Destination : The destination network or host. Gateway : The gateway address or ’*’ if none set. Genmask : The netmask for the destination net; 255.255.255.255 for a host destination and 0.0.0.0 for the default route. Flags : Possible flags include

     U (route is up)
     H (target is a host)
     G (use gateway)

Window : Default window size for TCP connections over this route. Iface : Interface to which packets for this route will be sent. irtt : Initial RTT (Round Trip Time). MSS : Default maximum segment size for TCP connections over this route.

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

Answer <cli prompt=“$” comment=“$”> 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 21144 0 0 0 12711 0 0 0 BMRU eth1 1500 0 13448 0 0 0 17388 0 0 0 BMRU lo 16436 0 12 0 0 0 12 0 0 0 LRU </cli>

Add your explanation here:

The netstat -i displays statistics for the network interfaces currently configured. It prints all interfaces present in the kernel, not only those that have been configured currently. The MTU and Met fields show the current MTU and metric values for that interface. The RX and TX columns show how many packets have been received or transmitted error-free (RX-OK/TX-OK) or damaged (RX-ERR/TX-ERR); how many were dropped (RX-DRP/TX-DRP); and how many were lost because of an overrun (RX-OVR/TX-OVR).

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

Answer <cli prompt=“$” comment=“$”> Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 gw-jupiter.swan-:domain *:* LISTEN tcp 0 0 jupiter.swan-icc:domain *:* LISTEN tcp 0 0 localhost.locald:domain *:* LISTEN tcp 0 0 localhost.localdoma:953 *:* LISTEN tcp6 0 0 *:ssh *:* LISTEN tcp6 0 0 ip6-localhost:953 *:* LISTEN tcp6 0 0 jupiter.swan-icct.c:ssh saturn.swan-icct.:48974 ESTABLISHED </cli>

Add your explanation here.

-t switch is used to show the current TCP chimney offload state in place of the typically displayed TCP state i.e. the active TCP connections. This particular command, the netstat -ta will give you a list of all servers that are currently running on your system.

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=“$” comment=“#”> icct@leda:~$ traceroute titan.saturn.icct.com traceroute to titan.saturn.icct.com (192.168.3.35), 30 hops max, 60 byte packets 1 jupiter.icct.com (192.168.2.1) 0.502 ms 0.492 ms 0.483 ms 2 * * * 3 titan.saturn.icct.com (192.168.3.35) 5.969 ms 5.964 ms 5.953 ms

</cli>

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

Answer <cli prompt=“$” comment=“#”> icct@leda:~$ 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) 0.511 ms 0.498 ms 0.483 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>

Explain the result:

When you attempt to set a connection between your computer and another computer(or from a client to a server), the connection is established using indirect contact through packets that travel through routers and gateways in order to reach to the destination required. In this question particularly 'traceroute' is used to trace the path of the connection between the network(host) I am on and another network and that is www.swan.ac.uk . The reason why the output is in form of stars “* * *” is because packets are sent to the destination but no reply is being given back due to certain reasons as firewall and so on. So we can conclude to reasons why connection might fail between two networks or servers. One would be if a packet or a node(gateway/route) failed or if the receiving destination has certain restrictions as mentioned above.

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

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

Answer

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

I hereby submit this work for marking.

Your signature here:

Jumana