Hi Amy and Brian, Thanks for the replies. I have looked on isaserver.org and lots of other sites, but can't find anywhere that says how to bypass the web filters within ISA Server itself. Lots of articles say how to use the firewall client or secureNAT client, but we have a bespoke application with the proxy details hard coded. I was trying to avoid changing anything at the client end, like installing the firewall client software. From what I understand, the application is accessing the ISA server like Internet Explorer does, (as a web proxy?) Any requests are processed by the firewall access rules in ISA. It is these rules that I want to modify or add to to try to bypass the web filters for certain sites. Is this possible without installing software at the client end? Thanks, Richard