Attempting to add a new Scanner host to the Messaging Gateway (SMG) Control Center fails with a message indicating that the Scanner host is incompatible.
 

BrightmailLog.log

Mar 09 2016 20:59:42 [http-41443-Processor6] INFO - Response content length is not known
Mar 09 2016 20:59:42 [http-41443-Processor6] ERROR - Cannot retrieve the Scanner mailwall identifier on host 192.0.2.105. Check that the Agent is running and allows connections from this IP address.
Mar 09 2016 20:59:43 [http-41443-Processor6] ERROR - com.brightmail.common.InvalidStateException: The Scanner host you tried to add is incompatible with your Control Center host. Please try again to add the Scanner. If that fails, please perform an OSRestore on the Scanner host, to the same version of Symantec Brightmail Gateway as your Control Center

agent_log

2016-03-09T20:53:19-08:00 (ERROR:2149.3034844080): [43015] Command handler: invalid component ID
2016-03-09T20:59:43-08:00 (ERROR:2149.3043236784): [43058] Command handler: unrecognized command: GET-MAILWALL-ID.
 

The software version installed on the scanner host does not match that of the Control Center host.

You MUST bring the Scanner to the same version as the Control Center using one of the following methods:

1. Upgrade the Scanner from CLI to the same version as the Control Center.
2. OSRESTORE the Scanner to the same version as the Control Center.

Once the Scanner is at the same version level as the Control Center, you will be able to add it to the Control Center successfully.