You need AmiTCP:l/inet-handler and AmiTCP:devs/inet-mountlist. You can find them from 
AmiTCP-bin-30b2.lha for example.
If you take them as-is, you need to put them somewhere and point AmiTCP: assign to this dir.
Or you can copy AmiTCP:l/inet-handler to L: and edit AmiTCP:devs/inet-mountlist accordingly and put it to DEVS:
Anyway, once done, put this to s:user-startup
mount TCP: from AmiTCP:devs/inet-mountlistIf you edited the mountlist and put the files to L: and DEVS: then add:
mount TCP: from DEVS:inet-mountlistWARNING: inet-handler adds a slight security hole to the system. To open the system for remote access, malicious application would only need to do something like this: 
newshell TCP:6666Attacker can then connect to the system remotely via telnet or netcat, and give arbitrary shell commands.