On 2016-04-22 at 15:20, Brian wrote: > On Fri 22 Apr 2016 at 18:29:11 +0100, Lisi Reisz wrote: > >> On Friday 22 April 2016 18:04:36 The Wanderer wrote: >>> I'm talking about what it uses for detecting duplicates so it can >>> discard them >> >> That is worth my while to investigate. I am a bit pushed at the >> moment, but will report back. > > It's a waste of time. Even if you conclusively demonstrated the > offending header was Message-Id: (and it almost certainly is a major > player) what would you do? Better is to avoid providers who think it > fine to mess with your mail. People wouldn't accept Royal Mail or the > US Postal Service doing it. > > As for duplicates: are the mails sent to the list and the one sent > back duplicates? That is, identical in every regard?
No; at minimum, the mails which are sent back have the List-ID header added, identifying the mailing list through which the message has been processed. (In my experience, usually there are other variances as well.) Google appears to treat them as if they were, however. That being precisely the problem. -- The Wanderer The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man. -- George Bernard Shaw
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