CS472 Computer Networks
Fall 2008
Homework Assignment # 2b
Due Date: Monday, October 20th, 2008 at 5:59pm
NOTE: Assignments must be submitted in electronic format to [email protected].
All the work must be original, no team work. Late assignments will not be accepted. Please
submit your assignment as your firstname and lastname as a zip file (e.g. mine would be
mkain_hw2b.zip)
Objective
This assignment asks you to implement a popular network protocol by interpreting and
implementing the specifications of an RFC. You will be writing a DNS server which is to
interact with the client you have already written. There are also questions about the security of
the protocol to be turned in with the client submission.
Problem
In Part B of the assignment, you are to implement a DNS cache server. You are to implement a
TCP CONCURRENT server (any of the three models discussed in class are acceptable) and an
UDP server.
You are to write the client code in C, C++, or Java ONLY. Libraries such as the libnsl, libresolv,
and libsocket with C/C++ and the package java.net are the ONLY permissible libraries that you
can use for socket programming. In case you do need to use some other library, please confirm
with the Professor and the TA first.
It is your responsibility to ensure that the code runs on tux.cs.drexel.edu or is entirely portable to
be run by the TA anywhere. Code that doesn’t meet either of these two requirements will be
graded as a zero. ALL source code must be available to the TA for inspection.
Input / Command Line
The server program should accept the following command line arguments:
The first argument is required and is the filename that logs all the messages received by and
generated by the server. Each message is to be logged in a single line. The message should
include some timestamp, client identification (IP address and port number) and the data sent.
The last argument is required and denotes the port number for the server to run on (since there
already is an DNS server running on port 53, you will have to specify a different number).
A sample command line would be:
dnsserver serverlog 5353
