Looking for a Microsoft person who can help w/ v6 and Office365 email
owens.bill at gmail.com
Wed Apr 22 15:08:07 CEST 2015
On Wed, Apr 1, 2015 at 8:02 PM, Bill Owens <owens.bill at gmail.com> wrote:
> We've been running our Office365 mail account for a few weeks now with
IPv6 enabled. We went into this knowing that Microsoft was going to enforce
SPF checks on inbound mail, and we've run into a number of issues with
people sending mail over v6 transport and having bad SPF records (or none).
So far we've been able to resolve all but one of those issues, or are in
the process of doing so; that's not a big deal. The one that won't fix
their record is going to require us to resubscribe to a few mail lists, not
the end of the world.
> However, we've discovered that there are sporadic failures even when
there are valid SPF records, and in some cases even when the email enters
the Microsoft 'world' using v4 and transitions to v6 between two Microsoft
servers - at which point the SPF check is applied even though the message
was "accepted" several hops prior, and the check sometimes fails. That's
something we can't fix on our own.
I don't know whether this is in response to the problems we've reported,
but Microsoft has changed their attitude towards SPF and
IPv6 just a little. Rather than returning a 5xx error code, which causes
the mail to bounce immediately, they're going to return 4xx
and allow the sender to attempt redelivery. This ought to prevent the
majority of bounces that we've been seeing, although it
doesn't fix the underlying issue(s) that cause the false SPF failures:
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