Am 24. Juli 2020 18:03:54 MESZ schrieb Klaus Ethgen via mailop <mailop@mailop.org>: >I debugged with Bjørn Bürger (thanks for helping) and found out that the >error is "weist große Ähnlichkeit zu früheren Spam Nachrichten auf".
I might add: This was the error message shown to the end user in Gmail. The headers of that test mail where completely clean, clean SPF- and DKIM passes, no blacklisted sending ip, Ipv4 delivery, etc. Interestingly, using the 'not spam' button did not change the result for the next mail. It might be safe to assume that some spam detection mechanism at Google just went crazy, considering some of the other observations on this list. Klaus never sent email to my account before that test, so there was definitely no accidental spam-tagging involved on my side. Unfortunately, Google does not add additional headers which indicate the type of match, like spamassassin and alike used to do it historically. This would definitely help with debugging. As to the Ipv4 vs Ipv6 theories: I tested an Ipv6 only setup for more than a year, located on a hetzner root server, with only clean DNS entries, a SPF ~all record, no DKIM. Nothing else. I have never seen any problem like this during the test period. Volume was from several messages per day to ~2500 messages per hour. The only difference was, that Google postmaster console starts to show useful information only above several hundred messages per day. So, maybe all these stories like "you need Ipv4 to deliver to Google" are just outdated admin vodoo folklore. Bjørn K9mail _______________________________________________ mailop mailing list mailop@mailop.org https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop
