Hi Everyone I managed to solve the problem ;). The thing that caused loss of NTLM authentication was an anti-virus software known as AVG 8.0 my version 8.0.156. It has an option called Web Shield . Disabling the above made everything work flawlessly. Regards -- View this message in context: http://www.nabble.com/NTLM-authentication-loss-tp18808476p18826776.html Sent from the Squid - Users mailing list archive at Nabble.com.