Re: gmail.com - 550 error for ipv6/PTR ?

[Ted Cooper <ml-nanog090304q () elcsplace com>]

On 15/01/14 10:06, Brandon Applegate wrote:
> Off-list replies are fine to minimize noise, and if there is an answer
> or any meaningful correlation I will reply on-list.  Thanks in advance
> for any info/feedback.

I have been running into these a lot also and have so far concluded that
it is an error within Google. The PTR/AAAA, SPF and DKIM are all matched
up and tested as working. It also occurring on domains using google apps
to handle their email so it is platform wide. All of the emails are
personal emails, but coming from multiple domains/senders.

The exact same email will be rejected when sent to any google IPv6
server for minutes/hours, but 3-4 hours later it will be accepted
without error.

The fact that it is being hard rejected is really quite annoying and
generating a lot more support work.

Unfortunately, my only fix at present is to turn off IPv6 delivery for
all google hosted domains as I encounter them. It would be really nice
if it was fixed.

My theory is that they are failing PTR lookups.