SMTP(8)

NAME
smtp - SMTP outbound channel for MMDF

SYNOPSIS
smtp (called by deliver)

DESCRIPTION
The SMTP outbound channel is part of the MMDF mail system. Smtp is called directly by deliver. It follows the standard deliver/channel protocol and handles outbound SMTP traffic. Smtp uses the channel configuration string to specify what it should place in the HELO string of the SMTP transaction. This will override the use of locname for this function. The following is a typical SMTP channel description from the mmdftailor file:

MCHN    smtp, show=``SMTP/TCP'', que=smtp, tbl=smtp,
    pgm=smtp, mod=reg, ap=822, confstr=``SERING.UUCP''

If host= is specified in the channel description, then the specified host is looked up in the channel table and used as the connect host regardless of the host to which the mail is addressed. This is useful when offloading mail addressed to a variety of destinations to a gateway for further delivery.

Smtp uses the RHS of the channel table as the IP address to which to connect. Alternate IP addresses may be specified by putting additional lines in the channel table with the same LHS. For example:

    FOO.BAR: 192.5.58.3
    FOO.BAR: 10.3.0.8

In this case, the smtp channel will attempt connection to 192.5.58.3 first. If the connection fails or if the remote SMTP server doesn't start up in reasonable time, the next address will be tried. In the case of nameserver-type channel tables, multiple IP addresses are tried based on the available MX entries for that host.

SEE ALSO
deliver(8), submit(8), smtpd(8), RFC821, RFC974