Trouble That May Occur When the Windows Server Firewall Is Set

This section explains the various problems that may occur when a firewall is set, along with possible causes and remedies.

Symptom: Service information fails to be retrieved when automatically retrieving domain information.

Cause	Communication with the DNS server is blocked due to firewall settings.
Remedy	Unblock port 53 (the default port) for the UDP protocol and TCP protocol. The DNS server normally uses port 53 to perform communications with the UDP protocol, but as data over a certain size may be processed using the TCP protocol, unblock port 53 for both the TCP protocol and UDP protocol.

Symptom: Active Directory Authentication has failed. (The <Authentication server not operating.> error message appears.)

Cause	Active Directory Authentication is blocked due to firewall settings.
Remedy	Unblock port 88 (the default port) for the UDP protocol and TCP protocol. Active Directory Authentication normally uses port 88 to perform communications with the UDP protocol, but as data over a certain size may be processed using the TCP protocol, unblock port 88 for both the TCP protocol and UDP protocol.

Symptom: User authentication has failed.

Cause	Communication for LDAP searches is blocked due to the firewall settings.
Remedy	Unblock port 389 (the default port) for the TCP protocol. User data is retrieved from Active Directory using LDAP searches. By default, LDAP searches are performed using the TCP protocol with port 389. Therefore, unblock port 389 for the TCP protocol. (If the port number used for the TCP protocol has been changed, unblock the port number used by the TCP protocol.)