Re: [ietf-smtp] [Emailcore] Proposed ESMTP keyword RCPTLIMIT

George Schlossnagle <> Sun, 18 April 2021 23:47 UTC

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From: George Schlossnagle <>
Date: Sun, 18 Apr 2021 19:47:15 -0400
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To: John Levine <>
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Subject: Re: [ietf-smtp] [Emailcore] Proposed ESMTP keyword RCPTLIMIT
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As a commercial MTA and ESP provider, this proposal is very exciting to
me.  Today we guess at these things and largely guess at things based off
of either observed behavior or out-of-band discussion with those operating
the receiver side of the email exchange.  Having this defined in the
session would be great.


On Mon, 15 Mar 2021 at 19:47, John Levine <> wrote:

> It appears that Sam Varshavchik  <> said:
> >MXes which do not announce their limits are going to dominate for some
> time.
> >So, I still need to do this for the foreseeable time. So, what does this
> >SMTP extension buy me? The only thing I can think of: not duplicating
> >messages when I don't need to.
> >
> >But the thing is: I don't recall anyone raising this to me, as a
> problem.
> >This is not on my radar screen as a problem that wants to be solved.
> I wouldn't think that your users would be very interested, but bulk
> mailers are desperate for
> any hints about how much mail they can stuff at people without getting
> blocked or rate limited.
> R's,
> John
> _______________________________________________
> ietf-smtp mailing list

chief evangelist