On Thu, Aug 21, 2025 at 8:10 AM Marcel Becker via mailop <mailop@mailop.org> wrote:
> > On Thu, Aug 21, 2025 at 7:06 AM Russell Clemings via mailop < > mailop@mailop.org> wrote: > >> 550 5.7.9 This mail has been blocked because the sender is >> unauthenticated. Yahoo requires all senders to authenticate with either SPF >> or DKIM. Authentication results: DKIM = FAILURE - SPF xxxx.xxx with ip >> 209.85.214.178 = FAILURE. See >> https://senders.yahooinc.com/smtp-error-codes/#authentication-failures >> for more information. >> > > >> It looks to me as if Yahoo is expecting the "from" field to pass SPF >> instead of (or in addition to) the envelope sender. Or is there a different >> issue that I'm not seeing? >> >> > You could follow the link in the SMTP message... > I did. > > It seems your users are sending emails via their Google consumer accounts > with domains in the "from" field, which are not properly set up to send via > Google's servers. > > Interesting point. I know you used to be able to spoof a "from" address when sending from Gmail even if it was just an alias. Now you have to have an actual mailbox at the alias domain. I'll try to do a test later today with a spoofed "from" field using a different account and see if the results change. > We require SPF or DKIM and we require either SPF or DKIM to align. > > Solution is to sign with an aligned DKIM domain. > I'm not sure how to do that with a spoofed "from." > > -- Marcel > > > _______________________________________________ > mailop mailing list > mailop@mailop.org > https://list.mailop.org/listinfo/mailop > -- =============================================== Russell Clemings <rclemi...@gmail.com> ===============================================
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