Adding an external Proxy server
I have a PFsense already running. I now have an external Blue Coat proxy server. Is it possible to configure the PFsense so that every user will be directed through the proxy server?
you could try following post, i've not attempted it myself
run squid in transparent mode on the pfsense firewall and configure squid to use the bl
uecoat proxy as a parent cache. some additional squid config is required.
Sure, if it's configured to run in transparent mode, you can forward the necessary port(s) to it (as marcelloc suggests in the link that heper gave).