SMTP: How the SMTP World Communicates with the Gateway (87047)


The information in this article applies to:

  • Microsoft Mail Gateway to SMTP 3.0
This article was previously published under Q87047

SUMMARY

The Microsoft Mail Gateway to SMTP always connects to the designated SMTP host to send messages. The gateway receives messages from any host that can connect to the gateway.

When using TCP as the transport mechanism, a TCP connection is made by the sender to the receiver's service port 25. A host that wants to send mail to the gateway initiates a connection to the gateway's service port 25.
Modification Type:MajorLast Reviewed:11/5/1999
Keywords:KB87047
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