Network protocol probing toolhttp://freeworld.thc.org/thc-amap/
Amap allows you to probe IP ports for running protocols, ignoring the port number. It does this by sending probe packets to the port and analyzing the responses. This will allow you to find services running on non-standard ports.
Having nmap installed is suggested, since amap cannot scan for open ports (but there is an option to import nmap's output).