[comp.protocols.tcp-ip] HELP ON TELNET?

mcguire%nrl.DECnet@NRL3.ARPA ("NRL::MCGUIRE") (07/09/88)

I am looking for ANY help on using TELNET to connect to other computers
and to other networks (ie. BITNET).  I can't figure out all those
@, %, ! symbols in the mail address.  

I've heard about gateways, but don't know how to use them.

Can anyone help me out, or tell me where to find more information? 

Thanks.

T. McGuire