I have Squid's new installation 3.3.3 behind a Firewall NAT and do not achieve that it works. Placing the debug in ALL, 3 I obtain the following mistakes: HTTP/1.1 400 Bad Request Server: squid/3.3.3 Mime-Version: 1.0 Date: Wed, 01 May 2013 12:19:08 GMT Content-Type: text/html Content-Length: 3229 X-Squid-Error: ERR_INVALID_URL 0 Vary: Accept-Language Content-Language: en X-Cache: MISS from proxy02 Via: 1.1 proxy02 (squid/3.3.3) Connection: close In the web browser I obtain: The following error was encountered while trying to retrieve the URL: / Invalid URL I have Squid's installation 2.7 working without problems. Does it change radically the installation into Squid 3?