Starting July 26, we have seen an increase of legitimate messages being rejected due to DMARC policy. Those numbers keep increasing daily and peak today at 18000% of our regular values.
Messages affected seem to be forwards by Postini to Google. IPs failing are on the ip4:64.18.0.0/20 range (which is part of our SPF btw). Today's leading Postini IP failing is 64.18.0.97 (PTR name: exprod5mx274.postini.com), but all other IPs from that range stay close behind. Unfortunately, we do not have any message samples. The rejection happens when Postini sends to Google. We do not have access to the email at this point. We receive the DMARC report as policy is set on our sender domain ( r.groupon.com). But failures happen on Postini's side for what seems to be auto-forwards. Google posted here <https://support.google.com/a/answer/6067440?hl=en>: "If you have customized SPF and DKIM settings in Postini, the transition tool doesn’t move these to Google Apps." One theory: If a receiver, using Postini, moved to Google Apps and has customized SPF/DKIM, the process could break. But those are just assumptions as no other information can be found at this point. Does anyone here see similar behavior or can provide more insights into why Postini's sends fail authentication to Google? Thanks! *Torsten Reinert* *Team Lead Americas, Email Deliverability* Email: [email protected] Groupon Inc. | www.groupon.com
_______________________________________________ dmarc-discuss mailing list [email protected] http://www.dmarc.org/mailman/listinfo/dmarc-discuss NOTE: Participating in this list means you agree to the DMARC Note Well terms (http://www.dmarc.org/note_well.html)
