DTC Configuration Overview
Typically, the DTC is installed on each Microsoft Windows 2000 Server, Windows XP, Windows Server 2003, Windows Vista, Windows Server 2008, Windows°7, Windows Server 7, Windows Next, and Windows Next Server system, and therefore each system has its own instance of the DTC.
In some cases, transactions can be more efficient when two or more systems are configured to share a single DTC transaction manager. For example, on a server cluster, a single instance of the DTC services the entire cluster. If a transaction touches multiple nodes, the transaction manager performs only a single log write. If each system had its own transaction manager, each would write its own log records.
If an application performs transactions spanning two or more computers, you must ensure that these computers are configured to communicate with each other. The DTC can propagate transactions from one system to another only if the DTC process on the first or primary system can communicate with the DTC process on the secondary system. However, a network configuration problem on either system can prevent the DTC processes from successfully communicating with each other. This causes a "Failed to enlist error" on applications.
All DTC process-to-process communication takes place using Local Remote Procedure Calls (LRPC), Remote Procedure Calls (RPC), or the Transaction Internet Protocol (TIP).
Non-administrative users must have the appropriate access rights to view and modify DTC configuration settings. Otherwise, any attempt to view or modify DTC configuration settings causes a permission denied message to appear. If the user has read access only, the DTC administrative user interface appears but all administrative functions are grayed out.
The DTC uses the following system services:
The DTC uses the NTLMSSP service to encrypt the XA database open string that it stores in the DTC log file. The DTC uses the XA open string when it opens an XA database to perform recovery. The open string is encrypted to help protect any user IDs and passwords that are in the open string.
The DTC uses the RPCSS service to communicate between DTC components.
The DTC configuration options are described in more detail in the following topics in this section: