We are configuring squid for windows as our proxy server. We also have a mcafee appliance and need to direct outside requests thru it.
We configured squid to listen to our internal net, go direct to internal web servers, and forward to mcafee for everything else.
For all requests to the outside we get "The requested url could not be retrieved." If the squid system is pointed to our windows AD/DNS server the message is "The domain name does not exist." If we point to our unix DNS server the message is "The name server refuses to perform the specified operation." If we remove all DNS entries on the squid system, (as recommended in a red hat link, I couldn't find anything for windows), the message is completely different, "The connection was refused when attempting to contact the proxy server you have configured. Please check the proxy settings and try again."
The test client is running firefox.
When we don't point squid to the mcafee box and have the proper DNS entries in place everything works fine.