Looking for a Microsoft person who can help w/ v6 and Office365 email

Ted Mittelstaedt tedm at ipinc.net
Wed Apr 22 17:21:22 CEST 2015

Very good!

Notice that only the threat of losing customers motivated them to do 

When you are a customer of a vendor and the vendor abuses you - only a 
credible threat
of leaving to find a competitor will motivate the vendor to fix the problem.

"working with them" or "giving them a chance" of "cutting them slack" is
appeasement - and it never works.

Very glad to see one more barrier to IPv6 adoption knocked down.


On 4/22/2015 6:08 AM, Bill Owens wrote:
> On Wed, Apr 1, 2015 at 8:02 PM, Bill Owens <owens.bill at gmail.com 
> <mailto: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:
> 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.
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