That message did not have a DKIM header ... or was so garbled that we didn't extract it.
Due to DKIM replay, we may spam reject forwarded messages that DKIM verify but not SPF, but those would not have that rejection message. And yes, we are continuing to ramp no auth, no entry. I'm sure I've had a long explanation on here in the past year, but the short answer is if the message is not DKIM valid and you're forwarding, you should rewrite the MAIL FROM to a domain you own that will SPF authn the message... and try not to forward spam. Brandon On Tue, Sep 12, 2023 at 6:00 PM Jason R Cowart via mailop <[email protected]> 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 > 554 5.0.0 Service unavailable > > > > This is occurring in situations where our users forward their mail to a > personal Gmail account. SPF checks will of course fail in the scenario, > but DKIM checks should pass. In fact, they most often do pass—users > impacted by this are only seeing a small subset of their mail from a given > sender bounced (which often times will be a Gmail sender). In cases where > the user retains a copy locally we’ve been able to verify that the DKIM > signature was present and was successfully validated by our system. > > Is anyone else experiencing this? > > Is anyone from Google could reach out to me off-list to discuss that would > be much appreciated. > > > > Best, > > Jason Cowart > > Stanford University IT > _______________________________________________ > mailop mailing list > [email protected] > https://list.mailop.org/listinfo/mailop >
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