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Path: utzoo!utgpu!water!watmath!clyde!rutgers!lll-lcc!ames!oliveb!tymix!feldman
From: feldman@tymix.UUCP
Newsgroups: comp.mail.misc
Subject: Re: Interactive SMTP over phone lines
Message-ID: <1209@tymix.UUCP>
Date: Wed, 6-May-87 21:15:34 EDT
Article-I.D.: tymix.1209
Posted: Wed May  6 21:15:34 1987
Date-Received: Sat, 9-May-87 06:46:24 EDT
References: <351@hqda-ai.UUCP>
Reply-To: feldman@tymix.UUCP (Steve Feldman)
Organization: Tymnet NTD, Cupertino CA
Lines: 24
Keywords: smtp sendmail interactive modem

In article <351@hqda-ai.UUCP> merlin@hqda-ai.UUCP (David S. Hayes) writes:
>I see a mail transport agent.  Sendmail should be told to talk
>smtp to the TA.  The TA dials, then just acts as a pass-through.

This is exactly what we did in order to get mail to other hosts on
Tymnet which speak SMTP but not TCP.  If a mailer definition is set up
in sendmail.cf with no $u (username) field in the mailer arguments,
sendmail will assume that it's speaking SMTP to the mailer program through
pipes on its stdin and stdout.  (This doesn't seem to be documented anywhere,
I discovered it while perusing the source.)

I wrote a mailer program which builds a Tymnet virtual circuit to the SMTP
server on the requested host and gets out of the way, passing data between
the stdin/stdout pipes and the network circuit.

You would have to do something similar, dialing the phone instead of
building a Tymnet circuit of course.

If you want a copy of the mailer program, let me know and I'll be glad
to send it to you.

	Steve Feldman
	Tymnet McDonnell Douglas
	..!sun!oliveb!tymix!feldman