On Wed 13/Sep/2023 02:14:29 +0200 Jason R Cowart wrote:
We are seeing an increasing number of bounces by Gmail related to failed
authentication checks. The bounces include language like:
<<< 550-5.7.26 This mail is unauthenticated, which poses a security risk to the
<<< 550-5.7.26 sender and Gmail users, and has been blocked. The sender must
<<< 550-5.7.26 authenticate with at least one of SPF or DKIM. For this message,
<<< 550-5.7.26 DKIM checks did not pass and SPF check for [mcn.org] did not pass
<<< 550-5.7.26 with ip: [67.231.157.125]. The sender should visit
<<< 550-5.7.26 https://support.google.com/mail/answer/81126#authentication for
<<< 550 5.7.26 instructions on setting up authentication.
z6-20020a05622a028600b00403a8e58423si1377805qtw.448 - gsmtp
[...]
Is anyone else experiencing this?
I get this language, on forwarding:
Remote-MTA: dns; gmail-smtp-in.l.google.com [74.125.71.27]
Diagnostic-Code: smtp; 550-5.7.26 Unauthenticated email from intesasanpaolo.com
is not accepted due to
550-5.7.26 domain's DMARC policy. Please contact the administrator of
550-5.7.26 intesasanpaolo.com domain if this was a legitimate mail.
Please
550-5.7.26 visit
550-5.7.26 https://support.google.com/mail/answer/2451690 to learn
about the
550 5.7.26 DMARC initiative.
t16-20020a05600c451000b003fee9453d8csi1042282wmo.59 - gsmtp
MAIL FROM was rewritten so as to pass SPF. ARC sealing the message provided no
benefit except checking, from the bounce, that the body hash in AMS matched the
one on the original DKIM signature, which had passed. The message was
legitimate and none of the signed headers,
h=date:from:to:cc:message-id:subject:mime-version:content-type was altered.
Why should I contact the administrator of the original sender?
Best
Ale
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