Hi, I set up a Squid3 Proxy on my Centos 5.3 box, and it works properly since I try to setup authentication on my Active Directory. Here is an extract of my squid.conf, inspired of my old squid 2.7 configuration : ______________________________________________________________________ auth_param ntlm program /usr/bin/ntlm_auth --helper-protocol=squid-2.5-ntlmssp auth_param ntlm max_challenge_reuses 0 auth_param ntlm max_challenge_lifetime 2 minutes auth_param ntlm children 10 auth_param ntlm realm Authentification Squid auth_param basic program /usr/bin/ntlm_auth --helper-protocol=squid-2.5-ntlmssp auth_param basic credentialsttl 1 hours auth_param basic children 5 auth_param basic realm Authentification Squid acl SSO proxy_auth REQUIRED http_access allow SSO _______________________________________________________________________ When I try to start the proxy service, I obtain this error message : [root@localhost mnt]# service squid start 2009/09/04 09:17:51| Processing Configuration File: /etc/squid/squid.conf (depth 0) 2009/09/04 09:17:51| Can't use proxy auth because no authentication schemes are fully configured. FATAL: ERROR: Invalid ACL: acl SSO proxy_auth REQUIRED Squid Cache (Version 3.0.STABLE16): Terminated abnormally. CPU Usage: 0.011 seconds = 0.003 user + 0.008 sys Maximum Resident Size: 0 KB Page faults with physical i/o: 0 Any idea to help ? Regards