> The reason Message-ID is SHOULD rather than MUST? Mail clients
> sometimes send messages without one to their submission server, which
> adds it on their behalf. As for why Google enforces it anyway:
> spam. Messages with minor RFC violations are far more likely to be
> spam, so rejecting them is a reasonable heuristic. In practice, Google
> and Microsoft have become the de-facto standards bodies for email —
> what the RFCs say matters less than what their servers accept.
Surely the problem is on Google's end? And a metaproblem is that we are allowing corporations to change or ignore standards for critical infrastructure?
> sometimes send messages without one to their submission server, which
> adds it on their behalf. As for why Google enforces it anyway:
> spam. Messages with minor RFC violations are far more likely to be
> spam, so rejecting them is a reasonable heuristic. In practice, Google
> and Microsoft have become the de-facto standards bodies for email —
> what the RFCs say matters less than what their servers accept.
Surely the problem is on Google's end? And a metaproblem is that we are allowing corporations to change or ignore standards for critical infrastructure?