stacks interacting over LAN? (newbie)

[sims]

>
>The effort to build and contribute an open-source chat program (or 
>programs) is fantastic, and credit should go to the correct people - 
>so I'm very sorry about getting this wrong.

I'm curious about what security concerns that a chat (or sockets in 
general) might open up
for the user and what (if any) precautions need to be taken.

Also, when setting up a chat for someone who has a firewall (uses a 
proxy) in place and
the Rev  "set the HTTPProxy to host:portNumber"  is used, are other 
security concerns
presented?

My questions spring from an appalling lack of knowledge of sockets  :-/

sims
EuroRevCon  2006!