Dear All, I am now using a squid proxy server which use ldap ( Windows Server 2003 Active Directory ) as authentication. I have use the squid module squid_ldap_group to achieve this. The following line shows the configuration: external_acl_type InetGroup %LOGIN /usr/lib/squid/squid_ldap_group -b "dc=example,dc=com" -D "cn=ldap,cn=users,dc=example,dc=com" -h example.com -w password -f "(&(objectclass=person)(sAMAccountName=%v)(memberof=cn=%a,ou=group,dc=example,dc=com))" -R I define the AD with "exmaple.com" rather than IP address. As I terminate the network connection of the first AD server. The proxy clients cannot authenticate by using LDAP. It seems that the proxy clients didn't know how to authenticate with the second AD server. Would you provide some information if squid supports this function? Any help would be greatly appreciated. Thanks and Regards, Cowking -- View this message in context: http://old.nabble.com/Squid-with-LDAP-server-failover-tp26312618p26312618.html Sent from the Squid - Users mailing list archive at Nabble.com.