(1)

Use the Readme.txt file that is included in the DTCPing.exe download to test Remote Procedure Call (RPC) and Distributed Transaction Coordinator (DTC) communication from Server1 to Server2. If this test is successful, run the test from Server2 to Server1.

Note that if RPC cannot flow in either direction, MS DTC communication fails in both directions. If RPC communication fails, the DTCPing window (on either server) displays this failure, which is also saved in the associated dtcping.log file. See the Readme.txt file for more information. If the test fails in either direction and the log indicates the failure is in RPC communication, continue to the next step. If the test fails in either direction and the log indicates the failure is in DTC communication, continue to step 9 below.  


(2)

If RPC has failed in at least one direction (for example, from Server1 to Server2), direct your firewall administrator to make sure that the Internet Control Message Protocol (ICMP) is open in both directions.

NOTE: You can typically determine if RPC has failed by reading the dtcping.log file.

By default, ICMP is port1. You can verify this in your protocol file, which is located in the %windir%\WinNT\System32\Drivers\ folder. Ping Server2 by NetBios name from Server1. If the ping fails, continue to the next step. Otherwise, continue to step 4.  

(3)

Ping Server2 by IP address from Server1 to make sure that the correct port is open for a ping on the firewall. A Network Monitor trace can verify this. If the IP address ping succeeds and the NetBios name ping fails, there is a name resolution problem.

NOTE: You can use the ipconfig /all command to retrieve the IP address(es) of a server.

A quick way to test name resolution is to make an entry in the Hosts file of the client server. This is the server on which the NetBios name ping fails. You can model your entry after the sample entry that is included in the file.

NOTE: You must only make an entry in the Hosts file for troubleshooting purposes. If the new entry corrects the name resolution problem, remove the entry from the Hosts file, and make the entry you must in the DNS, the WINS server, or the LmHosts file.

Other solutions to name resolution problems exist, but they are outside the scope of this article. 

(4)

If pinging Server2 from Server1 by NetBios name fails, or if pinging Server2 from Server1 by NetBios name succeeds but the DTCPing test shows RPC communication still fails, it is possible that Port 135 (the End Point Mapper, or EPM) has not been opened bi-directionally on the firewall. Check the firewall to make sure that the EPM is open in both directions. At this point, a Network Monitor trace may help to pinpoint the problem. 

(5)


You only reach this step if the DTCPing test indicates RPC communication works in both directions. If DTCPing indicates no errors in either direction, then RPC and MS DTC communication is flowing properly. 

(6)

If DTCPing indicates that DTC communication has failed in at least one direction (for example, from Server1 to Server2), direct firewall administrators to verify that the ports are open that the developer specified when the developer went through the MS DTC configuration article (see step 3). Additionally, some rules may be applied to the firewall that prohibits RPC callbacks for either (or both) servers. A Network Monitor trace may help to troubleshoot this particular scenario.  

(7)

If DTCPing returns an error message similar to the following: 
Unexpected: My session guid is same as partner's guid 
check whether the current server has been duplicated or cloned from the other server. If so, locate the HKEY_CLASSES_ROOT\CID key in the registry. Under this key, you may notice more than one GUID. Locate the GUID whose underlying Description key is MSDTC. Note that this GUID is also listed in the DTCPing output window. If the other server has a GUID that is exactly the same for MS DTC in its registry, you must create a new GUID for MS DTC in one of the registries. You can use GuidGen to do this.

After you add this new GUID, and also all of its underlying keys to HKEY_CLASSES_ROOT\CID, make sure to delete the old GUID that it is replacing.

If this step resolves your problem, it is highly recommended that you read the following article to learn more about duplicating (or "ghosting") computers:
162001 (http://support.microsoft.com/kb/162001/EN-US/) Do Not Disk Duplicate Installed Versions of Windows