MSDTC communication fails over VPN

Question

I have an application that runs transactions spanning over multiple databases on the same server. Naturally this involves the Microsoft Distributed Transaction Coordinator and everything works like it is supposed to.

Howver, when I remotely connect to the network where the server is hosted via VPN and run the application on my local machine I receive the following error:

System.Transactions.TransactionManagerCommunicationException: "Communication with the underlying transaction manager has failed."

Caused by:

System.Runtime.InteropServices.COMException: Error HRESULT E_FAIL has been returned from a call to a COM component.

Here is the stack trace for the originating exception:

at System.Transactions.Oletx.IDtcProxyShimFactory.ReceiveTransaction(UInt32 propgationTokenSize, Byte[] propgationToken, IntPtr managedIdentifier, Guid& transactionIdentifier, OletxTransactionIsolationLevel& isolationLevel, ITransactionShim& transactionShim)
at System.Transactions.TransactionInterop.GetOletxTransactionFromTransmitterPropigationToken(Byte[] propagationToken)

The problem arises only when I connect to the server through a VPN tunnel.
Note also that I have temporarly disabled Windows Firewall on my local machine, just to be sure it doesn't block the MSDTC.

Does anyone know of any issues when running MSDTC through VPN?

Answer 1

Do you administer the VPN connection? There might be restricted ports on the VPN. Likewise, do you administer your servers? Your servers might only allow connections from IP addresses on the inside and not on the segment used for VPN service. If you are the administrator, perhaps saying which VPN software you are using will help.

Answer 2

I suggest you run DTCPing (available from the Microsoft site somewhere) This is run at the same time on both machines and detects all manner of DTC problems.

Be careful I had great difficulties with this tool until I actually read the instructions and started both sides of the test up before I clicked the start test button.

Answer 3

I'm having the same problem using a Windows 7 x64 client and a Server 2003R2 server. I have been able to make it work (on the same vpn, same server) using XP, Vista x86, and Windows 7 x86. I have a support call with Microsoft open and they are looking into it. I'm curious - what operating system are you guys using on your client machines?