How should I choose a port number for my server?
The list of registered port assignments can be found in STD 2 or RFC
1700. Choose one that isn't already registered, and isn't in
/etc/services on your system. It is also a good idea to let users
customize the port number in case of conflicts with other un-
registered port numbers in other servers. The best way of doing this
is hardcoding a service name, and using getservbyname() to lookup the
actual port number. This method allows users to change the port your
server binds to by simply editing the /etc/services file.