Try netcat.
Code:
nc -l -p [localport] -e [program]
The above will start listening on the specified local TCP port and when an incoming connection is made on that port the program of your choice is executed (try /bin/bash for a shell). Note that this is suicide security wise. Oh, and since this is Linux you cannot listen on privileged ports without being root. And listening like in the above command, as root, will only result in you being completely rooted and your machine turned into a SPAM relay and/or server for spreading pirated pr0n.
Håkan
How to open/close ports in a shell prog ?
