MSDTC and firewall

Question

We are using MSDTC for SQL transactions. I am having issue with setting up firewall for MSDTC to work. The application and SQL are running on separate machine. Currently MSDTC is working if i turn off firewall on application server. I think there should be someway to add exception to the firewall setting for some ports. So that firewall can still be ON and DTC will not have any issues. I am not sure of the ports to add in firewall setting (I did try adding port 135 with no success)

Solution

Have your Firewall allow port 135 and the dcom port range. By default, the dcom port range is 1024-65535. Thats a big range to open up. You can limit this range in the registry or using dcomcnfg. This post describes this:

http://blogs.msdn.com/distributedservices/archive/2008/11/12/troubleshooting-msdtc-issues-with-the-dtcping-tool.aspx