[TriLUG] Fwd: mail relay through trilug.org?

[Scott Lambdin]

The Helo/Eloh chit chat.  If you look at the actual interchange, it looks
the same whether the connecting machine is a client or a server or even a
human typing commands in a terminal.

It never says by the way I am a pine session so treat me like a punk.

--Scott

On 7/10/07, Tanner Lovelace <clubjuggler at gmail.com> wrote:
>
> On 7/10/07, Scott Lambdin <lopaki at gmail.com> wrote:
> > On 7/10/07, Tanner Lovelace <clubjuggler at gmail.com> wrote:
> > >
> > > Port 587 - (See RFC2476).  This is the mail submission port.  It only
> > > takes
> > > incoming mail from mail clients, not mail servers. (I believe)  You
> must
> > > first do STARTTLS to encrypt the channel, then SMTP AUTH to log in
> > > and only then will it let you relay mail.
> >
> >
> >
> > I think clients and servers are not distinguishable in smtp.
> >
> >
>
> No, you're not looking at it correctly.  Postfix on ports 25 and 465 are
> acting
> as "Mail Transfer Agents" or MTAs.  On port 587 it is acting as a "Mail
> Submission Agent" or MSA.  From the RFC 2476:
>
>   SMTP was defined as a message *transfer* protocol, that is, a means
>   to route (if needed) and deliver finished (complete) messages.
>   Message Transfer Agents (MTAs) are not supposed to alter the message
>   text, except to add 'Received', 'Return-Path', and other header
>   fields as required by [SMTP-MTA].
>
>   However, SMTP is now also widely used as a message *submission*
>   protocol, that is, a means for message user agents (MUAs) to
>   introduce new messages into the MTA routing network.  The process
>   which accepts message submissions from MUAs is termed a Message
>   Submission Agent (MSA).
>
> So, yes, in this case, they are definitely distinguishable.
>
> But, even in the general case, mail clients like thunderbird speak SMTP.
> No one will argue that T-bird is a server, so I fail to see what you're
> getting
> at here.  SMTP is a client server protocol, which means that there will
> be clients and there will be servers.  Servers may then turn around and
> act
> as clients too, but they don't have to.
>
> Cheers,
> Taanner
> --
> Tanner Lovelace
> clubjuggler at gmail dot com
> http://wtl.wayfarer.org/
> (fieldless) In fess two roundels in pale, a billet fesswise and an
> increscent, all sable.
> --
> TriLUG mailing list        : http://www.trilug.org/mailman/listinfo/trilug
> TriLUG Organizational FAQ  : http://trilug.org/faq/
> TriLUG Member Services FAQ : http://members.trilug.org/services_faq/
>