Re: Anybody aware of SMTP AUTH tunnel software?

From: Donald Thompson (dlt_SPAMCATCH_at_lunanet.biz)
Date: 11/30/03 

Date: Sun, 30 Nov 2003 08:31:15 GMT

Jem Berkes wrote:
> I'm probably not the only one who has run into this situation. The SMTP
> server through which I want to send my outgoing mail uses SMTP AUTH to
> authenticate sending rights.
>
> While it's possible to set up sendmail and postfix to use SMTP with TLS and
> AUTH I would rather use a tunnel approach to handle these layers, allowing
> any plain SMTP compliant software to reach the mail server that needs
> authentication.
>
> Is anyone aware of such an SMTP AUTH tunnel program? If none exists, I
> might write one over the holidays since I already have written the required
> code in my JBMail software.
>
> The way this could work is as follows. Your SMTP-compliant software
> (whatever it may be) could connect to localhost:1234, reaching the tunnel
> program. The tunnel would then establish a connection to
> mail.example.com:25 and transfer all SMTP communications verbatim, except
> that it would insert the AUTH command to authenticate to the remote server.
> The tunnel therefore needs to do very little; other then the AUTH command,
> all other data lines are transmitted unmodified.

Either I don't get what you need, or you're making this more complicated
than it needs to be. If you have box A that needs to do an SMTP AUTH to
box B in order to send mail out, why can't you just run a mail server on
box A which relays all outgoing mail to box B using SMTP AUTH, then
allow all necessary clients to relay through box A? At a minimum a
client should either be able to invoke sendmail on box A locally, or
connect to port 25 on box A, in order to send its payload. Writing a
tunnel program to do this would be like reinventing the wheel, except
that your wheel is in the shape of a sphere instead of a circle.

-Don

>

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