This object monitors the ability of DFS Replication to contact other members of the replication group, and creates a Warning alert if cannot reach a member of the replication group. It does so by looking for the presence of DFS Replication Event 5008.
An unhealthy state of this monitor indicates that replication failed because DFS Replication could not reach another member of the replication group. This can occur if the server is unreachable, often because the correct firewall ports aren’t open, or if DFS Replication is not running or installed on the server. DFS Replication will periodically retry replication.
Check Firewall settings
If a firewall has been configured between replication partners, ensure that it is not blocking RPC communication. DFS Replication depends on RPC for communication. DFS Replication uses the RPC Endpoint Mapper (port 135) and a randomly assigned dynamic port in the range of 49152 through 65535 for Windows Server 2008 R2 and Windows Server 2008, or in the range of 1025 through 5000 for Windows Server 2003 R2.
You can use the Dfsrdiag command-line tool to specify a static port instead of the dynamic port. For more information about how to specify the RPC Endpoint Mapper, see article 154596 in the Microsoft Knowledge Base (http://go.microsoft.com/fwlink/?LinkId=73991). For more information about dynamic port usage in Windows Server 2008, see article 929851 in the Microsoft Knowledge Base (http://go.microsoft.com/fwlink/?LinkId=187092).
Enable the Remote Procedure Call (RPC) service
To confirm that the Remote Procedure Call (RPC) service is running, type the following command at a command prompt window, where <servername> is the name of the affected server:
Sc query <servername> rpcss
If the server does not respond or it reports that the state is STOPPED, start the service by following the directions in Microsoft Knowledge Base Article 830071 (http://go.microsoft.com/fwlink/?LinkId=186948).
This monitor automatically resets to a healthy state after it detects that the issue is resolved.