Can Squid be used with a firewall?
If you are behind a firewall then you can’t make direct con- nections to the outside world, so you *must* use a parent cache. Squid doesn’t use ICP queries for a request if a) its on the other side of your firewall, and b) there is only one parent. The squid.conf file contains the parameter ‘inside_firewall’ tag, used to specify a list of domains internal to your Internet firewall.