I am not sure if it site or application centric, but I have some HTTP driven applications failing due to an error the the HTTP server sent invalid reply headers. I am running squid-3.HEAD-20080721 and I have not changed any of the settings in squid.conf with the exception of those mentioned in the QUICKSTART, and WCCP related items. So far the only application giving this error is apt-get on ubuntu. I don't know how to begin troublshooting this, but does anyone have suggestions on troubleshooting it, or fixing it? I can visit web sites like CNN just fine. I didn't want to post the whole squid.conf unless someone wants me to becuase it really is the default config for squid-3.HEAD-20080721. I have what so far is a working Squid3HEAD setup with TProxy and WCCP on CentOS 5.2 x86_64. Nick