SMTP: What the Gateway to SMTP Does

The information in this article applies to:

• Microsoft Mail Gateway to SMTP, version 3.0

The Microsoft Mail Gateway to Simple Mail Transfer Protocol (SMTP) polls the SMTP mailbag file on the gateway postoffice database and converts this file to an "SMTP message." Attachments are searched for non-7-bit characters and user unknown encoded (uuencoded) if any are found. 7-bit ASCII attachments are included in the message body.

The gateway then opens an SMTP connection with the designated SMTP host and sends the mail items. The host will route the message to its final destination.

Upon receiving mail, the gateway checks to see if the recipient is valid. If the recipient field is invalid, it fails the message, and the log file "user unknown."

A valid addressee results in the SMTP address being converted to a Microsoft mail address. Any attachments received are automatically uudecoded if necessary, and appear as attachments in the Microsoft Mail inbox.