- 550 error for ipv6/PTR ?

Franck Martin fmartin at
Thu Jan 16 01:35:02 UTC 2014

On Jan 14, 2014, at 4:06 PM, Brandon Applegate <brandon at> wrote:

> Just saw this in a message tonight.  No idea if this is a transient error or not.
> ---
> host [][2607:f8b0:4002:c01::1a]
>    said: 550-5.7.1 [2607:ff70:11::11] Our system has detected that this
>    message does not 550-5.7.1 meet IPv6 sending guidelines regarding PTR
>    records and authentication 550-5.7.1 . Please review 550-5.7.1
> [] for more 550
>    5.7.1 information. t26si2290895yhl.255 - gsmtp (in reply to end of DATA
>    command) ---
> That URL's relevant section says:
> Additional guidelines for IPv6
> The sending IP must have a PTR record (i.e., a reverse DNS of the sending IP) and it should match the IP obtained via the forward DNS resolution of the hostname specified in the PTR record. Otherwise, mail will be marked as spam or possibly rejected.
> The sending domain should pass either SPF check or DKIM check. Otherwise, mail might be marked as spam.
> ---
> I have both of these (PTR's RR has matching AAAA, and I have SPF (but not DKIM)).

It occurs to me, you may have sent a bounce, where the envelope from is empty, therefore SPF would work on the domain in the helo/ehlo. People often forget to put a SPF record there... So there may be no SPF in fact...

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