There is an RFC:
http://tools.ietf.org/html/rfc1122
Section 1.2.2 Robustness Principle
Ted
On 4/22/2015 8:40 AM, Frank Bulk wrote:
Glad to hear that Microsoft did this on their O365 platform.
Is there an RFC or other standard that we can point other email
providers to about implementing email admission in this manner?
Frank
*From:*[email protected]
[mailto:[email protected]] *On
Behalf Of *Bill Owens
*Sent:* Wednesday, April 22, 2015 8:08 AM
*To:* [email protected]
*Subject:* Re: Looking for a Microsoft person who can help w/ v6 and
Office365 email
On Wed, Apr 1, 2015 at 8:02 PM, Bill Owens <[email protected]
<mailto:[email protected]>> 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:
http://blogs.msdn.com/b/tzink/archive/2015/04/18/office-365-will-slightly-modify-its-treatment-of-anonymous-inbound-email-over-ipv6.aspx
Bill.
