Firewall ports needed for rpc error in powershell

Question

In my enviroment we use several different DMZ's to host our servers in. This creates a situation where some of the computers in the domains are in different subnets.  I am trying to run a script in one domain in which all the computers are
in the same subnet except for 2. In this case there is a firewall between the two subnets i am describing. When i try and run my script i recieve the error below. I have verified the following ports are open on the firewall.
TCP 5985, 5986, 445, 389    TCP\UDP 135
I have monitored our firewall and the ports being blocked when i run my script are TCP 4754 on one server and 5002 on the other. I believe these are DCOMM ports. What other ports or range of ports, or any other ports, do I need to open to resolve
the RPC error? I do not want to just open a bunch of unneeded ports between my DMZ's. I could just open these 2 ports and resolve the issue for now, but i am trying to make this a powershell friendly enviroment, if you take my meaning. I should mention all
local firewalls are turned off on the servers and the script runs fine on all other servers in the subnet.
Thank You in advance for your help
Get-WmiObject : The RPC server is unavailable. (Exception from HRESULT: 0x800706BA)
At C:\Users\jthomas99\Desktop\Get-IPDetails.ps1:14 char:16
+    $Networks = Get-WmiObject Win32_NetworkAdapterConfiguration -ComputerName $Co ...
+                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:) [Get-WmiObject], COMException
    + FullyQualifiedErrorId : GetWMICOMException,Microsoft.PowerShell.Commands.GetWmiObjectCommand
Thanks for your help

Answer 1

Here is the DCOM firewall configuration document.  It should be given to your firewall admins and they need to pay special attention to setting up the DCOM port forwarding rules.
http://support.microsoft.com/kb/154596/en-us
There are also instructions on how to configure DCOM ports to work with WAN/Internet access issues.
If you are looking to obtain remote management over a WAN or the Internet you can and should set up WMF as it can be run over a fully encrypted HTTPS port and it does not require odd dynamic port allocation
as does RPC.
You can also set up PowerShell Web Service which does not require dynamic ports and can be routed over any port.  It uses the browser to open a PowerShell session on a remote server that can have delegated access to other servers.  DCOM cannot
do this without making many dangerous changes t your network.
http://technet.microsoft.com/en-us/library/hh831611.aspx
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