XCON: Gateway Address Routing Table Information

Each Connector has an associated address space (or spaces) and a Connected Sites configuration. Both associations can be defined using the Exchange Administration program and can be replicated by the directory to or from adjacent sites. As this information is created by configuration and replicated by the directory, it is used by the System Attendant and the Message Transfer Agent (MTA) to generate a routing table called the Gateway Address Routing Table (GWART). Each server maintains its own GWART within its Directory.

The GWART is stored in the ds (on the site Addressing object in the gateway- routing-tree attribute); the Ems_rid.dll is the module that generates the GWART and can be called from admin ("Regenerate Routing" button) and MAD (based on the schedule). Renaming or deleting the GWART text file will have no impact on the routing information.

In order to successfully deliver a message, the MTA compares the recipient of the message to the GWART to determine through which group of connectors the message can be delivered. The final result of the search provides a group of Connectors which can deliver the message to the remote site.

The GWART is kept by the Directory. It can be viewed by an Administrator using the Site Addressing Object. The Routing property page displays the routing table as it has currently been calculated.

Under normal circumstances, the routing table is rebuilt when changes occur (changes are refreshed very quickly). If you want to force a re- calculation, click Recalculate Routing. You can view the contents of the GWART by using a text editor, such as Notepad. The GWART is located in the EXCHSRVR\MTADATA directory. Each time the routing of a server is updated, the GWART is updated and a single backup copy is saved for administrative reference only. The following is a list of the GWART files and its purposes:

Reading The GWART

The GWART can be segmented into three major areas. Each area corresponds with an address type, which Exchange uses to send mail. These address types are as follows:

Each line of the GWART indicates an available path which the MTA can use to route messages to a destination.

When the MTA makes a routing decision, it scans through the GWART to find an address space that matches the address of the message. If an available address space is identified, the MTA routes the message to the associated connector. Obtaining details on any GWART entry reveals the associated connector in a Routing Details dialog box.

Sample GWART Diagram

For troubleshooting purposes, it is recommended that you view the GWART. You can save the GWART as a text file, and open it as a text file using a text editor. The following diagram graphically represents the connections for the sample GWART listed below:

Sample GWART: