Re: Dialup e-mail transfer

[Matti Aarnio <mea@nic.funet.fi>]

> Hi,
>   Matti Aarnio <mea@utu.fi> writes:
> 
> >   TURN
> >   502- Ok xxxxxxx, I will inform queue scheduler to trigger a transport
> >   502- session towards you.  You can close this SMTP session, but don't
> >   502- hang-up the TCP/IP connection!
> >   QUIT
> 
> Hmm. Is there a way to tell the scheduler to do this?

	There is some potential.

A not-well-known/documented feature can be used to cancel outgoing email
from LOCAL spool (emails which YOU sent you can cancel.) -- if the email
already went out from the machine, you can't get at it.
(I think it is in one of those old documents -- zmog.tex ?)

Similar magic-file email could be used to trigger the TURN, or an UDP
(sock_stream / pipe / ..) message could be used for it.

If you want to be able to do a real TURN where the session starts spewing
material queued for you to you in the session you have initiated, I would
like to know:
	1) a way to authenticate that you are entitled to receive the queued
	   files ?
	2) how to (minimum technology!) create the connection from the
	   smtp-server to the scheduler-started smtp-client ?

I think we can safely assume that Zmailer's queueing model can be used
with  $MAILVAR/db/routes  maps  "*.some.domain" to  "smtp!your.dialin.name"
Question comes, how it can trust you to be what you claimed with "HELO" ?

It could be fairly easy with a dialup-slip, assuming you do
	1) have static IP number
	2) can be positive that nobody else can get the same number
	3) confirm HELO-argument to match the IP
at that it might be acceptable to do a real TURN.

If you have dynamically allocated IP-numbers at your SLIP/PPP server,
you are off the deep end..

Hmm.. Ok, maybe a test-version can be created -- a KLUDGE in deed...

Still I am inclined to say that it is easier to run UUCP over a line
than to put there IP and then run SMTP with a real TURN  -- that is,
if email is your only target.  If you are looking for more features,
and just put the IP up once a while, then a trigger-TURN used to
trigger queue sending as soon as line has been started by the dialer
side is doable. -- heck, such could have more uses even -- "retry this
queue now" when debugging some transporter...

Ok, I will think about that.

> -- 
> Matthias Urlichs        \ XLink-POP Nürnberg  | EMail: urlichs@smurf.noris.de
> Schleiermacherstraße 12  \  Unix+Linux+Mac    | Phone: ...please use email.
> 90491 Nürnberg (Germany)  \   Consulting+Networking+Programming+etc'ing     42

	/Matti Aarnio	<mea@utu.fi> <mea@nic.funet.fi>