Smtplib module

David Bolen db3l at
Mon Oct 22 23:31:12 CEST 2001

Sheila King <sheila at> writes:

> On 22 Oct 2001 15:05:00 -0400, David Bolen <db3l at> wrote in
> comp.lang.python in article <u1yjvwl5v.fsf at>:
> :Sheila King <sheila at> writes:
> :
> :> Do an MX record look up on the domain name in the email address, and
> :> deliver directly to that SMTP server.
> :
> :Even that won't guarantee you know about the status of final delivery,
> :since the published MX record may well just point to the entry point
> :into a larger delivery system that can cross any number of additional
> :machines.
> You're not the first to discuss what the final delivery status of the
> email was. It is curious to me, since I never discussed that topic, nor
> did the original poster ask about the final delivery status. He asked
> about whether it was accepting for delivery.
> Is this some obsession, or is it some FAQ such that people jump to that
> assumption?

I do think it's a common misconception that people get when they first
start dealing with the underlying protocols that are involved in mail
delivery, and can be easily fooled by result codes from an SMTP server
that might make them believe final delivery has occurred.  But that's
not why I specifically brought it up here.

The original post may not have asked about it, but the post to which
you were replying included the paragraph (albeit not quited in your

> Gerhard =?iso-8859-1?Q?H=E4ring?= <gh_pythonlist at>:
> I was thinking about the general problem of finding out if an email
> address exists and if mails get delivered. This is of course much more
> complex, and AFAIK not solvable in the general case.

and while reading the whole thread I probably assumed (presumably
incorrectly given the above) that your suggestion about trying the MX
lookup might improve things by turning a handoff for eventual delivery
into a local delivery which had been discussed in the thread as
actually getting an accurate code out of the delivery agent.

Given that you weren't suggesting that (using it to get closer to the
final target for better error status), then I'm somewhat confused as
to why anyone would bother with a manual MX lookup.  It seems of
dubious benefit to just duplicate what your local mail system is
already (presumably) configured to do very well.

-- David
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