A proxy is not required to use a PIX firewall. It may help though with some rules. I'd use a proxy with a PIX - firstly because it gives you two layers of security between the outside world and your internal network, secondly becuase your PIX rulebase will be pretty messy without one, and lastly because it's so much more easy to manage using two seperate devices - one for URL blocking and one for your standard rulebase!

A proxy is not required to use a PIX firewall. It may help though with some rules. I'd use a proxy with a PIX - firstly because it gives you two layers of security between the outside world and your internal network, secondly becuase your PIX rulebase will be pretty messy without one, and lastly because it's so much more easy to manage using two seperate devices - one for URL blocking and one for your standard rulebase!