Windows Discovery/Add Workload fails with 'RPC Server Unavailable'

  • 7005541
  • 24-Mar-2010
  • 27-Apr-2012

Environment

PlateSpin Migrate
PlateSpin Protect
PlateSpin Forge

Situation

When attempting to discover or add a Windows workload the operation fails with:
 
RPC Server Unavailable
 
In addition, a job does not get created in the PlateSpin Client.

Resolution

This error is normally cause by firewalls.
 
RPC Server Unavailable generally means that the PS server was able to connect on ports 135/445 but the ephemeral port connection back to the PS server was not successful.
 
Windows RPC connections initially connect on 135/445 and the server being called randomly selects a port above 1024 to connect back to the PS server, it is this connection back that is not successful.
 
1. Confirm the ports in question are open and try again.

 

Windows firewall being enabled is a common cause.

 

2. This issue can also occur if a NAT is in place. Windows RPC/DCOM connections are have problems NAT'ed connections. This is a problem that is native to Windows and can be worked around in the following ways:

 

i. Move the PS server to the same side of the NAT device as the server being discovered to avoid the NAT altogether.

 

ii. Manually discover the server and import the results into the PlateSpin Client.  

 

Microsoft has published technical articles on how to limit the port range for DCOM and RPC:

 

Using Distributed COM with Firewalls

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dndcom/html/msdn_dcomfirewall.asp

 

How to configure RPC dynamic port allocation to work with firewalls

http://support.microsoft.com/default.aspx?scid=kb;en-us;154596

 

DCOM Does Not Work over Network Address Translation-Based Firewall

http://support.microsoft.com/kb/248809

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