* Making it transparent, so clients don't need any web browser proxy server settings, is also very possible. You use iptables (also already installed and running) to forward port 80 traffic to the squid server port 3128. I tried but didn't get it working. I was sure how to remove the iptables entries, so I just turned that service off and all was back to normal.

** Referring to [http://tldp.org/HOWTO/TransparentProxy-5.html TransparentProxy howto]

** others say you can use DHCP or DNS to forward to the proxy too