SMTP: Configuring the Gateway to Use Company Domain Names

The information in this article applies to:

• Microsoft Mail Gateway to SMTP, version 3.0

Incoming Mail

The Microsoft Mail SMTP Gateway needs to receive mail with an address that can be associated with a single postoffice in order to route mail to the appropriate postoffice. If you have more than one postoffice, the gateway needs to receive addresses with different domain names and at least one unique name per postoffice.

Most companies like to be able to give addresses as USER@COMPANY.COM instead of USER@PO.COMPANY.COM. This means that another process has to change the address from USER@COMPANY.COM to USER@PO.COMPANY.COM before the mail gets to the SMTP gateway. This is usually resolved by having an alias file (one record per user) or .FORWARD files for each user on some TCP/IP host that routes mail before it gets to the SMTP gateway. The alias file or .FORWARD file changes the address from USER@COMPANY.COM to USER@PO.COMPANY.COM before the mail gets to the SMTP gateway. Consult the administrator of the Mail Routing Host for details on accomplishing this.

Outgoing Mail

The SMTP gateway can be configured to send outgoing mail with the "from" field address USER@COMPANY.COM. In the Mail Administrator program, select Gateway, SMTP, Address Map, Create. Then create an additional address map for each postoffice. In this second entry, type COMPANY.COM in the SMTP Domain field. Now each postoffice has two address map entries. It is important that in each case the first entry is the company domain name, COMPANY.COM. When the gateway processes outgoing mail, it finds the first occurrence of Network/PO, and uses that SMTP domain name, which in this case is COMPANY.COM. When incoming mail arrives, the gateway finds the first occurrence of PO.COMPANY.COM, and sends it to the appropriate Network/PO.

The file being changed by the Mail Administrator program is M:\SMTP\ADDR_MAP.CFG. This file can also be edited at the MS-DOS command prompt to ensure the entries are in the correct order.