Originally Posted by rednuht
setup ethereal (now called wireshark), it will capture all network traffic, you will be able to see what ip address the chat packets are coming from.
might be a bit confusing to start with but you will soon recognise what its doing.
Won't the chat packets originate from the chat server and not the client? When my girlfriend comes online I'll try this out (cuz I know her IP address). I've never done any "real" detective work with ethereal but I suppose this would be a great start.
Edit: As a side note... doesn't sound like much of a friend if you need to find other ways of finding out if s/he's home or not...