DTC firewall requirements?

Question

I am trying to set up an environment in which a TransactionScope created on a web server (asp.net) will transfer the transaction through WCF to the application server and then through the database. Since I am forced to use a SQL Server 2005 database, this often leads the transaction to “move” to a distributed transaction (in this TransactionScope, you could wrap several service calls), which means that you need to enable the distributed transaction coordinator .

I successfully processed it in a local field where the web server and application server are located on the same computer, connecting to a remote database. DTC reports port 135 for RPC connections (as well as in the upper range). I don’t have two boxes configured for testing ... for DTC to work, do I need to open port 135 (from the point of view of the firewall) for communication between the web server and the application server or just on the application server in the database? I get a push from people to deploy about opening 135 from the Internet to an application server, I was wondering if this was even necessary. I have not yet found a doc online that clarifies this to me.

The kind of fringe question was hoping for some understanding from someone who might run into this.

Hello,

GA

Answer 1

I think this is worse than when the DTC uses RPC calls for coordination. You may be able to fix them to a specific range of ports, but this is difficult. I had a project with similar problems - using more than one connection even on the same server as the DTC requests. I ended up refactoring code for sharing connections after an unsuccessful attempt to move on to firewall issues. I could get it to work in our QA environment, but not in production. There were some differences: QA - all virtual machines, production was real equipment on the SQL server and grouped. The OS loads were as similar as possible, but there might have been minor differences in the patches because the QA field had a wider range of applications than the production field.

This MSDN article may be helpful: http://support.microsoft.com/kb/306843