>> Why don't you use an existing mail server? Probably because that was his homework assignment for a networking class. Not uncommon to be told to implement a server from the scratch from the RFC. Although that does not explain his concern about performance.
Abhinav, if that is the case, using sockets is more or less the same from any language. Python as usual will be cleaner than C. You might want to look at Twisted Mail. Use SocketServer module in the standard library to implement the RFC. Other than that it is silly to try to write a Mail Server unless you have some extra ordinary need. -- http://mail.python.org/mailman/listinfo/python-list