Re: Mailing list usage questions

[Jeffrey Walton <noloader@gmail.com>]

On Tue, Apr 11, 2023 at 10:12 PM The Wanderer <wanderer@fastmail.fm> wrote:
>
> ...
> Some mail services apparently treat this "discard incoming messages that
> look like duplicates of ones you already have a copy of" behavior as a
> feature; Gmail is the best-known example. That has problems when (as
> with this mailing list) the incoming copy is not identical to the one
> that was sent, even though it has the same Message-ID, but AFAIK they
> don't seem to care.

I believe Message-Id's are supposed to be unique across space and
time. It sounds like discarding the duplicate is expected behavior (to
me).

I don't think I would blame GMail for that. Maybe it's the sender's MUA?

Also see https://en.wikipedia.org/wiki/Message-ID .

Jeff