Hi, I also use iptables and squid, but just for my own bandwidth savings.
In the past I have found this page useful and current....
http://www.linuxhomenetworking.com/w...ess_with_Squid
I thought the default port was 3128, but I guess you can use what you like as long as the rest of the system knows about it.
see how you go, best wishes, Glenn