Workaround for sending mails to google with IPv6 3

If you see

host[2607:f8b0:400d:c02::1b] said:
550-5.7.1 [2607:5300:101::79e] Our system has detected that this message
does 550-5.7.1 not meet IPv6 sending guidelines regarding PTR records and
550-5.7.1 authentication. Please review 550-5.7.1…tication_error for more 550
5.7.1 information. h1si3408978qew.71 – gsmtp (in reply to end of DATA

the destination dropped your connection due to (incomplete) IPv6-settings.

In this case one of theses checks failed:

Your hostname need a IPv6 recrd (AAAA) in your bind-zone that points to the IPv6 address of your server.

Your IPv6 address must have a reverse dns record that points back to the hostname.

If you can´t fix both settings, you can send to google over IPv4 only.

Disabled IPv6 completely in postfix is quite simple. Just set
in the and restart postfix.

AFAIK only google uses such a strict restriction. You can use IPv6 to connect other mail-server. In this case just set the protocol for google to IPv4 as described in send mail with postfix for certain domains using ipv4 or ipv6 only

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3 thoughts on “Workaround for sending mails to google with IPv6

  • Nylz

    Vielen vielen Dank! Habe echt lange rumgefummelt an meinem postfix. Bin jetzt fast Experte in DMARC, DKIM & SPF… aber trotzdem kam irgendwann von gmail wieder dieser IPv6-Error.
    Dein Tipp hat mir wirklich endlich geholfen!
    Hoffentlich bleibt das jetzt auch so… bis die bei Google mal wieder ihre Guidelines anziehen…

  • Andy

    Ist bei jetzt auch so! Andere werden bald nachziehen, aber ich denke das dauert noch mind. 2-3 Jahre. IPv6 ist halt nicht der Hit, IPv4 war bzw. ist so schön easy.

    • Florian Schaal Post author

      I don´t think that IPv6 is very different to IPv4. You must always define your addresses and set valid ptr-records. It makes no difference if you add ipv6-subnet oder ipv4-subnet to a system.