Other applications are using the same ephemeral port as the Sophos Update Manager (Port 51234) and after following article 65930 "How to change the port which Sophos Update Manager (SUM) uses to communicate with the Remote Management System agent" and rebooting the server, the port conflict returns.
The Sophos Agent log shows an error like:
An uninitialized socket was created.
Failed to connect to the SUM host: connection was refused
First seen in
Sophos Update Manager
Sophos Enterprise Manager
Windows 2003 and Windows 2008
Other third-party applications are using ephemeral ports in the same range as the Sophos Update Manager and happen to use the same port that SUM has been configured to use. On reboot, the port set in article 65930 is used by a third party application and as a result the Sophos Update Manager can't communicate with the Remote Management System (RMS) Agent.
What To Do
You will need to configure a reserved port for Sophos Update Manager with Windows so that this port does not get assigned to another application.
Microsoft have a number of knowledge base articles detailing the steps required for Windows Server operating systems. See below.
Windows 2008 and Windows 2008 R2
An example of the command from the above Microsoft is:
netsh int ipv4 Add excludedportrange tcp 51234 1 persistent