Issue description   

ADManager Plus fails to detect domain controllers (DCs). This issue prevents administrators from performing user and group management, policy enforcement, or other Active Directory (AD) related operations.

This issue can be identified through error messages such as The given server is not operational, missing DCs in the ADManager Plus console, or failed synchronization with AD.

Possible causes   

• Network connectivity issues: Firewalls or network configurations blocking communication between ADManager Plus installed server and DCs.

• Incorrect permissions: The service account lacks permissions to query DCs.  

• DNS misconfiguration: DCs not registered in DNS or incorrect DNS records.  

• DC issues: DCs offline, demoted, or improperly configured.  

 Prerequisites   

• Administrative access to ADManager Plus and DC.  

Resolution   

Step 1: Verify network connectivity  

1. Ping the DC from the ADManager Plus server and run <DC_IP_or_Hostname>

2. Ensure ports like 389 (LDAP), 636 (LDAPS), and 3268 (Global Catalog) are open. Test with, TNC <DC_IP> 389.

3. If the ports are closed, create a firewall inbound rule to allow traffic.   

Step 2: Check connection between ADManager Plus and DC

1. Download the DMZ Port Analyzer link and launch the application.

2. Enter the hostname or IP address of the DC.

3. The second screen will display the status of ports specific to ADManager Plus.

4. Review the list of required ports and confirm they are Open for proper ADManager Plus functionality.

5. If ports are blocked, update your firewall settings accordingly.

Step 3: Validate DNS configuration

Use nslookup to verify that the domain controller is resolving to the correct IP address:

1. Open Command Prompt on the ADManager Plus server.

2. Run nslookup <DomainControllerName> to check the IP address of the DC.

3. Ensure that the returned IP address matches the expected IP of the DC.

4. If the IP is incorrect or not resolving, check the DNS settings on the ADManager Plus server and ensure it is using the correct DNS server (preferably a DC).

Step 4: Reconfigure the domain controller list

1. Log in to ADManager Plus.

2. Navigate to Directory/Application settings > Active Directory.

3. Edit the domain and click Discover Now or Add More DCs.

4. Provide the service account password and click Update.

Related topics and articles 

• Simplify Active Directory management

• Active Directory group management

Tips   

1. Monitor DC health using tools like dcdiag.  

2. Keep ADManager Plus updated for bug fixes.  

How to reach support