810:088:90 - Network Security
                 Assignment One - Due Monday, July 14th, 2003

 1.  A packet is coming from www.dartmouth.edu to your machine in 
     the CEEE room 20 classroom/lab.

     Recall that your IP number is your drone number with 100 added to
     it for the CEEE lab.  If you work at drone-14, for example, your
     IP number is 192.168.10.114 and recall that that lab is a class C
     network, so all machines had IP address of the form 192.168.10.z.


     a. Draw a diagram of the IP packet header as shown in the textbook 
        in Chapter 6.  You also have this diagram on one of your 
        Tuesday handouts from class #2.  We went over it during that
        class.

        Fill in as many of the fields as possible for the IP header.
        Use the ping, host, traceroute, tracert (Windows) and 
        nslookup commands as needed to find out the information.

        There are several possible correct answers for the TTL field,
        as that would depend on how congested the internet is when you
        track the route of packets sent from the dartmouth university
        server to your CEEE machine.

     b. Do the same for the TCP packet header for the packet delivered
        to your machine from the www.dartmouth.edu web server.

     c. What is the name of the web server at dartmouth?

     d. What is the class of network for the dartmouth.edu domain?  
        A, B or C.  Explain and show how you determined this, including
        the details.

 2.  You are trying to crack the following two encrypted messages.  You 
     can assume that each used a Caesar cipher, but not necessarily a key
     with value of 3.  (The key for each message is different, by the way).

     a.  SBJOZ EBZT
     
     b.  QMWWMWWMTTM

 3.  Convert the following numbers from binary to decimal, i.e. 
     from base 2 to base 10.  Show your work.

     a. 134
     b. 161
     c. 241
     d. 20

 4.  What is the IP address of the College of Natural Sciences web server,
     which is reached via www.cns.uni.edu?

 5.  Convert the following numbers from hexadecimal (base 16) to decimal.
     Show your work.

     a. B4
     b. 37C
     c. DC

 6.  Rewrite each of the following binary numbers in hexadecimal.

     a.  111101101100
     b.  10111101
     c.  111010001011

 7.  What command can you use to find out the standard port numbers 
     that are assigned for various services, when working on a Linux
     machine in the CEEE lab?

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 8.  Encrypt the word PANTHERS using the Vigenere Cipher and using
     the key UNI.

     Key        UNIUNIUN
     Plaintext  PANTHERS
     Ciphertext ????????