[plug] squid + ssh & mail [network newbie]

[sol]

On Sunday I set up my PC to act as a server (squid, apache, wu-ftpd, 
sshd) for two client laptops. It was a first-timers effort but 
everything went really well. However, I do have a couple of small 
problems. The clients can't receive mail from the remote servers, only 
the local server. And whilst I can ssh into the local server (my PC) I 
can't ssh beyond that. I can use mail (imap client - mozilla) and ssh to 
remote domains using the PC but not laptop clients which can only access 
the PC/server. The clients just can't locate external domains except 
using web browsers which have been configured for the squid proxy.

I thought that this was related to client ssh and client mail 
configurations, but I've been messing around with the mail 
configurations and can't seem to get any mail client to recognise the 
external mailserver domain. Is there something I need to tweak in 
squid.conf? Does ssh client have options that allow use of a proxy to go 
to external domains? Is this a proxy server problem or a proxy client 
problem?

thankyou,
sol