Homework questions for Chapter 12

 

  1. Log onto rex.nmhu.edu
  2. Run w and who. Who is logged in right now?
  3. Run ifconfig (/sbin/ifconfig)
    1. What is the MAC address of rex?
    2. What are the broadcast and subnet masks for rex?
    3. What is the maximum number of bytes of data in a single transmission for the Ethernet link?
    4. How many transmission and receiving collisions and errors have occurred since the Ethernet link was activated?
  4. Run dig and explain what you found.
    1. Rerun dig with the domain specified as nmhu.edu
    2. Rerun dig with domain gatech.edu
    3. Execute nslookup and dig on www.unm.edu

                                                               i.      Compare the two results for common information and present it.

                                                             ii.      What kinds of additional information did you get from dig.

  1. Run host and describe what you found:
    1. On jaring
    2. On tricera
    3. Run host -l nmhu.edu

                                                               i.      What are the name servers for highlands? [you may have to scroll up to the top]

    1. Use host to find out what machines at unm.edu handle their e-mail
  1. Run netstat and explain what you found.
    1. Run netstat –r. Describe what is in rex’s routing table.
    2. Run netstat –i. Describe what is in rex’s interface table. Where else could you get this information?
    3. Run netstat –a.

                                                               i.      List the active connections.

                                                             ii.      List the Internet servers on rex.

    1. Run netstat –N. How does it compare to netstat –a?
    2. Run netstat –s.

                                                               i.      How many TCP packets had to be retransmitted? Should we be concerned?

                                                             ii.      Are there more UDP packets sent or received? Explain why.

    1. What option would you use if you wanted to find additional information including the user id? [HINT – look in the man pages]
  1. Run arp (/sbin/arp) and explain what you found.
  2. Run rarp (/sbin/rarp) and explain what you found.
  3. Execute traceroute (/usr/sbin/traceroute) on www.jaring.my. Where is delay in the path? [You should try using neotrace so that you can identify the reason for the delay]

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  1. Visit http://www.ibr.cs.tu-bs.de/cgi-bin/sbrowser.cgi
    1. Select Agents and enter the IP address 207.66.121.164
    2. Use SNMPv2-MIB!system to determine the sysName for this device. What is it?
    3. What is the device’s OID?
    4. What is the uptime for the device?
    5. What is the device?
    6. What is the device’s location?
    1. Switch Agents to 207.66.121.156 and Use Walk: SNMPv2-MIB!system to determine information about another device. What is the device and where is it located?
    2. Switch Agents to 207.66.120.1 and Use Walk: SNMPv2-MIB!system to determine information about Highlands router.
    3. 192.132.89.66,69,73,104,107,142-3,146,148 all have SNMP enabled. Check these out and indicate whether we should be concerned.