This must be getting real old... it's still not working. I have now turned on full external ACL debugging and it produces output like the below: 2005/02/26 14:10:30| aclMatchExternal: ldap_group user not authenticated (-1) 2005/02/26 14:10:31| aclMatchExternal: acl="ldap_group" 2005/02/26 14:10:31| aclMatchExternal: ldap_group user not authenticated (-1) 2005/02/26 14:10:31| aclMatchExternal: acl="ldap_group" 2005/02/26 14:10:31| aclMatchExternal: ldap_group user not authenticated (-1) 2005/02/26 14:10:31| aclMatchExternal: acl="ldap_group" 2005/02/26 14:10:31| aclMatchExternal: ldap_group user not authenticated (-1) 2005/02/26 14:10:31| aclMatchExternal: acl="ldap_group" 2005/02/26 14:10:31| aclMatchExternal: ldap_group("epa\\aderooy gOpenProxy") = lookup needed 2005/02/26 14:10:31| externalAclLookup: lookup in 'ldap_group' for 'epa\\aderooy gOpenProxy' 2005/02/26 14:10:31| external_acl_cache_add: Adding 'epa\\aderooy gOpenProxy' =-1 squid_ldap_group WARNING, User 'epa\aderooy' not found in 'DC=estateprop,DC=com, DC=au,DC=local' 2005/02/26 14:10:31| externalAclHandleReply: reply="ERR" 2005/02/26 14:10:31| external_acl_cache_add: Adding 'epa\\aderooy gOpenProxy' =0 2005/02/26 14:10:31| external_acl_cache_add: updating existing entry 2005/02/26 14:10:31| aclMatchExternal: acl="ldap_group" 2005/02/26 14:10:31| aclMatchExternal: ldap_group = 0 The problem is, this only happens in Squid. I have tried the EXACT external ACL command line for squid_ldap_group many many times on the command line and it works perfectly. I use it with domain\\username and it works fine (with the -S parameter). But for some reason when called from Squid it is failing... It really makes no sense. This is plain 2.5STABLE7. Regards, Oliver