Data Protection Error ID: 308
Error ID: 308 appears when Firewall application blocks the DPM Agent traffic between the Host & the Client. If you’re using the Microsoft firewall or any other firewall application in your environment, you must allow the following TCP & UDP ports to allow the communication between DPM Host & Client.
TCP Ports:
5718, 5719, 135, 88, 139, 389
UDP Ports:
53, 88, 137, 138, 389
I use the Symantec Endpoint to protect my environment. Therefore, I have enabled the following two Firewall rules under Symantec Endpoint Network Threat Protection to allow communication between my servers & clients.
Above rules will immediately fix the issue, then you’ll be able to see that the DPM server communicates with its DPM clients properly. See below,
For more information refer the Microsoft Knowledge Base article 947682: http://support.microsoft.com/kb/947682