Hello ,

We have Windows 2012 R2 DFS R with remote site.

But It start working as soon as Server Restarted and again Replication again stop working after some time.

From network all PING is OK.

Is there any configuration missing in DFS R ?

EventID: 5008 - The DFS Replication service failed to communicate with partner Server1 for replication group Replication for Site mySite. This error can occur if the host is unreachable, or if the DFS Replication service is not running on the server. 

Partner DNS Address: Server1.mydomain.priv Optional data if available: 

Partner WINS Address: Server1 Partner

IP Address: 192.168.1.3

The service will retry the connection periodically. 

Additional Information: 

Error: 1722 (The RPC server is unavailable.) 

Connection ID: 4C312077-DD2C-405F-9D53-2C650DC01453 

Replication Group ID: AAB44F7C-52DF-48A2-8F92-129F51FBF6AC

 Based on the experience, TCP off-loading on the network level may be causing the issue.

Please add these following registry values to all DFSR replications partners to see it can be helpful.

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters

Value =DisableTaskOffload
Type = DWORD
Data = 1

Value =EnableTCPChimney
Type = DWORD
Data = 0

Value =EnableTCPA
Type = DWORD
Data = 0

Value =EnableRSS 
Type = DWORD
Data = 0

Please note: You will need to reboot the server for these changes to take into effect.

After the reboot monitor replication for the amount of time to see if the issue can be resolved.

You could refer to the below thread to troubleshoot the issue:

Errors with DFSR
http://social.technet.microsoft.com/Forums/windowsserver/en-US/3778427a-a594-4f1d-9c97-d8d1e6a56a83/errors-with-dfsr