Issue: You are getting the error: “The RPC Server is unavailable. (Exception from HRESULT: 0x800706BA)”
Cause: This error is likely caused by the RPC ports being blocked between the servers involved in the communication or server process you are trying to complete.
Background: RPC is categorized as the X11 protocol and is in the 6001 to 6032 port range. Commonly 6007 is what is being blocked in this case.
Diagnosis: You can test RPC connectivity from the server you are on to another computer/server using the following command:
Get-WmiObject Win32_ComputerSystem –ComputerName OTHERSERVER
If communications fail you will see output similar to the following:
If RPC communications are working between the servers you will output similar to the following:
You can also test specific ports, like 6007 using the telnet command. If telnet is successful and the port is open then you will see a blank screen. If telnet fails because the port is closed then it will simply time out as you can see in this example:
Resolution: Work on your firewall policies to make sure RPC is not being blocked. Many firewalls (Watchguard) will block RPC and SMB/NetBios (NetScreen) even when you have ‘any-any’ rules in place. In the case of WatchGuard you must specifically create a rule/policy to explicitly allow the RPC ports. In the case of NetScreen (ScreenOS) there is a checkbox in the rule to allow NetBios.