how to access computer on subnet from outside?

[nuttervm]

i have one computer running win2k as a ICS server for the rest of my small homenetwork. i want to telnet into my linux machine. if i were using a domain name, i would say 134.126.231.178, 192.168.0.172
where the first number is the ip of my ICS server, and the other is of course my local IP for the linux box.

i know i have done this before, i'm not sure of the syntax though.