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XCON: Gateway Address Routing Table Information

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This article was previously published under Q149121

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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.

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More 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:
   Filename      Purpose
   ----------    ----------------------------------
   GWART0.MTA    Current Routing table text file
   GWART1.MTA    Routing table prior to last change

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:
   Address Type        Description
   ------------        --------------------------------------------
   Distinguised Name   The native Microsoft Exchange Server address
   (DN)                format. These are reflected as type EX.

   Domain Defined      The format used for custom recipient storage
   Attribute (DDA)     (for example: MS and SMTP).

   O/R Address         The Native X.400 address type.

Each line of the GWART indicates an available path which the MTA can use to route messages to a destination.
   [    Address Space     ] [ cost ] [ connection 1, connection 2, .......]
   EX, /O=ORGNAME/OU=Site-X , 2      , Connector to Site-A, Connector to

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:
      To the Internet                   X400 Cloud (GB, Frisco)
          |                               / 
          |  IMC                         /  X400 Connector
          |  Cost = 1                   /   Cost = 1
          |                            / 
      + SATURN -----------------------+
      |                               |
      |         SITEz                 |
      +------------------------ PLUTO +
     /                            |
    /                             | MS Mail Connector
   /  Site Connector              | Cost = 1
  /   Cost = 1                    |
BSD                           MSNET/PO1

Sample GWART:
   EX,/O=WYNNWARE/OU=FRISCO;,1, Connection to Frisco
   EX,/O=MICROSOFT/OU=BSD;,1,Site Connector (BSD),
   MS,MSNET/PO1;,1,MS Mail Connector (PLUTO),
   MS,MSNET/PO2;,1,MS Mail Connector (PLUTO),
   SMTP,*;,1,Internet Mail Connector (SATURN),
   X400,c=GB;a=TMAILUK;p=*,1,Connection to Frisco,
   X400,c=US;a= ;p=MICROSOFT;o=BSD;,1,Site Connector (BSD),

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Keywords: KB149121, kbusage, kbinfo

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Article Info
Article ID : 149121
Revision : 6
Created on : 10/28/2006
Published on : 10/28/2006
Exists online : False
Views : 385