On Mon, 13 Dec 2021, Vsevolod Stakhov via mailop wrote:
On 13/12/2021 17:19, Alessandro Vesely via mailop wrote:
Hi,
I assume everybody knows that RFC 5322 allows multiple mailboxes in the
From: field. This feature existed in RFC822 already. I think it is to
be used for those cases where multiple persons are authoring a message,
albeit adding the list of coauthors is usually not done. This message
is an example. How many rejects does it yield?
Gmail reacts like so:
Action: failed
Status: 5.0.0
Remote-MTA: dns; gmail-smtp-in.l.google.com [108.177.119.27]
Diagnostic-Code: smtp; 550-5.7.1 [192.0.2.4 13] Messages with
multiple addresses in From:
550 5.7.1 header are not accepted. do22si22787062ejc.211 -
gsmtp
Is it customary to reject messages with multiple addresses in From:?
Why?
Best
Ale
This is a clear case where RFC is wrong and bogus when one takes into
consideration other Internet standards, for example DMARC or even DKIM.
There is also a clear way to implement the behaviour you've described
without such a violation: just add a Reply-To header with multiple
addresses.
https://serverfault.com/questions/554520/smtp-allows-for-multiple-from-addresses-in-the-rfc-was-this-ever-useful-why-do
reminds us that RFC822 explicitly allows multiple addresses in the From:
header, but *only* when there is also a Sender: with a single address,
which addresses the DKIM problem.
However RFC7489 section A.3 says that DMARC does not use the
Sender Header field, even though it would be logical to do so.
Rspamd has a high score rule to penalize messages with multiple from, as
I've seen just spam with multiple from headers in practice like other
people in this mailing list.
Does this rule consider the Sender header ?
--
Andrew C. Aitchison Kendal, UK
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