CS 480 M01 Fall 2022 - Homework Assignment #6

Points: 80 points total

1. 10 pts.
   The network 143.123.0.0/16 has been subdivided into /19 networks.
   1. How many networks are there? List them. What is their netmask?
   2. How many hosts could there be on each network?
   3. Determine which network the address 143.123.67.124 belongs to.
   4. What is the broadcast address for each network?
2. 10 pts.
   Host 128.138.2.4 on network 128.138.2.0/24 wants to send an IP packet to host 128.138.129.12 on network 128.138.129.0/24. Assume that
   • Host 128.138.2.4 has a default route through 128.138.2.1.
   • Host 128.138.2.4 just booted and has not sent or received any packets.
   • All other machines on the network have been running for a long time.
   • Router 128.138.2.1 has a direct link to 128.138.129.1, the gateway for the 128.138.129.0/24 subnet.
   1. List and explain all related Ethernet frames and IP packets that can be observed on the 128.138.2.0/24 network. Show the source and destination addresses of all packets transmitted (all addresses for both the Ethernet frames and IP packets).
   2. If the network were 128.138.0.0/16, would your answer change? How or why not?
   3. If the 128.138.2.0 network were a /26 network instead of a /24, would your answer change? How or why not?

3. 10 pts : man pages Read man pages (from sections 1, 5, or 8) for all the commands below (try the commands while reading its man page). In short paragraphs (3-5 lines in your own words - do not just copy parts of the man page) describe what is each command for. Choose an extra option (not the help nor version options) for each command listed and describe a situation in which you would use it.

   hostname (1)
   hostname (5)
   hosts
   ip
   ip-address
   ip-neighbour
   ip-route
   ping
   ss
   

4. 8 pts. Change Your Network Configuration With YaST
   Start YaST and select System / Network Settings.

   Under Global Options disable IPv6 (if enabled) and make sure that DHCP is NOT used anywhere else (look around - do not change default route via DHCP, do not set hostname via DHCP, ...).
   Also Change

   • the routing table - add or change the Default IPv4 Gateway (router) to be 192.168.8.101 (through eth0 device ) , and
   • Under Hostname/DNS change
     • the Static hostname in such a way that you append 'temp' to the current hostname (ivan would change to ivantemp).
     • Set Hostname via DHCP to no
     • Use Custom Policy STATIC
   • Under Overview change the already configured device :
     • Add 40 to the IP address (keep it statically assigned IP address; 192.168.8.11 would change to 192.168.8.51), and
     • change the netmask to /26 , and
     • change the hostname again to have "temp" appended to the name (if you haven't done so already at the end of the previous step).

   Apply the changes and close the YaST.
   Note that if you do this remotely through ssh then you will lose your connection to the machine (IP address has just chaged)...

   Create new directory /root/net_changes .
   Find all files under /etc directory that were modified due to the network config changes above and save the list into a file. Make sure that the files are listed in a long listing format similar to the output of ls -l. Name the file "network_changed_files_long_listing" :

   find /etc some_options_you_chose > /root/network_changed_files_long_listing
   

   Explain the command you used and investigate the changed files. In your report list and explain those files that are configuring network settings directly related to the network changes just made through YaST (hostname, IP address, default router, ...). Copy all of these relevant files into the /root/net_changes directory.
5. 8 pts. Change Your Network Configuration Manually
   • Modify (some of) the files found in the previous step above in order to change
     hostname: change the 'temp' into 'lab6' at the end of your hostname (ivantemp would change to ivanlab6)
     IP address: change your IP address per this list:

     192.168.8.71    ariyalab6
     192.168.8.72    benjaminlab6
     192.168.8.73    hunterlab6
     192.168.8.74    joshlab6
     192.168.8.75    loganlab6
     192.168.8.76    marcolab6
     192.168.8.77    shannonlab6
     192.168.8.78    stephenlab6
     192.168.8.79    timothylab6
     

     netmask: 255.255.255.0
     router / gateway : 192.168.8.1
     
6. 4 pts. Reboot and check that the network is configured correctly
   Check that the shell prompt displays correct name ( similar to ivanlab6:~ #) and
   run
     uname -a     You should see output similar to

   Linux ivanlab6 5.14.21-150400.24.21-default #1 SMP PREEMPT_DYNAMIC Wed Sep 7 06:51:18 UTC 2022 (974d0aa) x86_64 x86_64 x86_64 GNU/Linux
   
   

     ip a     You should see output similar to

   1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
       link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
       inet 127.0.0.1/8 scope host lo
          valid_lft forever preferred_lft forever
       inet6 ::1/128 scope host 
          valid_lft forever preferred_lft forever
   2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
       link/ether 00:50:56:3c:92:88 brd ff:ff:ff:ff:ff:ff
       altname enp2s1
       altname ens33
       inet 192.168.8.68/24 brd 192.168.8.255 scope global eth0
          valid_lft forever preferred_lft forever
   

     ip route show     You should see output similar to

   default via 192.168.8.1 dev eth0
   192.168.8.0/24 dev eth0 proto kernel scope link src 192.168.8.56
   

   In you report explain the the output of the commands above and make sure that all variables are set correctly.

   Check also that you can communicate with other computers. Do ping 192.168.8.1 (Stop the ping by [CTRL] + C)
   You should see output similar to

   itestlab6:~ # ping 192.168.8.1
   PING 192.168.8.1 (192.168.8.1) 56(84) bytes of data.
   64 bytes from 192.168.8.1: icmp_seq=1 ttl=64 time=0.182 ms
   64 bytes from 192.168.8.1: icmp_seq=2 ttl=64 time=0.249 ms
   64 bytes from 192.168.8.1: icmp_seq=3 ttl=64 time=0.185 ms
   ^C
   --- 192.168.8.1 ping statistics ---
   3 packets transmitted, 3 received, 0% packet loss, time 2038ms
   rtt min/avg/max/mdev = 0.182/0.205/0.249/0.030 ms
   	

7. 5 pts. Adding other hosts
   Add 3 lines to /etc/hosts for each of the hosts on cs480 network to include all possible names / IP addresses that the Vm host can have. For example, for the Ariya's machine you would have:

   192.168.8.11	ariya
   192.168.8.51	ariyatemp
   192.168.8.71	ariyalab6
   

   The other IP addresses / hostnames can be seen in /etc/hosts on lbc(csvm3). Don't forget the nametemp (IP + 40) and namelab6 from the list above.
   Also add IP addresses for the intructor's itest machines itest:

   192.168.8.4	itest
   192.168.8.7	itesttemp
   192.168.8.8	itestlab6
   	

8. 4 pts. ARP:
   Run the commands below (as user root and in the order listed), observe the output, and explain everything :

   ip neigh
   ping -c 3 itestlab6
   ip neigh
   ip neigh del 192.168.8.8 dev eth0
   ip neigh

Submitted files, overall quality, length, and feedback:

9. 5 points : Submit all relevant files you modified during the lab (into the /home/CS480/yourcsloginname directory as part of the tar.bz2 file) . Exactly two files need to be submitted: One file being your report in PDF is to be submitted on the Blackboard. The other file is the tar.bz2 file containing everything else and it gets submitted into /home/CS480 (Pack the files together using tar and bzip2, and copy them using scp from your computer into your cs account )
10.  10 points : Submit your report as a PDF document through learn.nmsu.edu and all supporting documents, programs, and execution transcripts as part of the tar.bz2 file in your directory under /home/CS480. The report has to contain answers to all questions above, and for the practical problems on your computer describe in detail choices you made, difficulties you encountered, and how did you deal with them.
11. 5 points : Feedback:In the last paragraph of your report estimate how much time you spent on this assignment. Describe what was hard, easy, interesting, boring or confusing.

Please remember the submission requirements:

Two files need to be submitted for every assignment :
1. The first file is your typed report .
   It has to be submitted through http://learn.nmsu.edu as one file / document and it has to be in the PDF format.
   No other format will be accepted. The name of the file has to contain your name and assignment/lab number separated by "_" (If your name is John Smith then the name of the document submitted for this assignment needs to be John_Smith_HW06.pdf).  
2. The second file to be submitted into your directory under /home/CS480 directory has to be a tar.bz2 file that contains all other files related to the assignment.
   It will contain all relevant files that you modified for the assignment. Everything that was done to finish the lab, modify your system, write, run and verify submitted programs and scripts used needs to be included in the submitted tar.bz2 file. That includes all your system configuration files modified for the lab/assignment as well as programs and scripts written (including complete source code, supporting shell scripts, test data input files, ...). The name of the tar.bz2 file has to contain your CS login name and the lab number separated by "_" (if your cs login name was jsmith then the file's name for this assignment will be jsmith_Lab06.tar.bz2 ).   The files submitted as part of the tar.bz2 file have to be exact copies as found on your cs480 lab system.

If you want to correct or add something to already submitted assignment than you need to do so before the deadline and resubmit the whole report again and also resubmit your new tar.bz2 file .

Please remember that late submissions are penalized 20% / day and NO submissions that are late 3 or more days will be accepted. You can be late at most 2 days to receive any points.