Milter-greylist

On 03/20/2015 10:15 AM, Brett Charbeneau brett@... [milter-greylist] 
wrote:
>        We have been seeing 5-21 hour delays from the time an Office365
> user sends us email and our users actually receiving it.
>        After several posts to the sendmail user list it appears
> (unsurprisingly) that Microsoft is only loosely adhering to the
> protocol when it comes to greylisting.
This is always frustrating to me when I talk to people about
Microsoft and to some degree Google.    They see the flashiest
fanciest car, but don't perceive that it doesn't have seatbelts
or other "boring" items.

I checked my mail logs for Greylisting related to a lot of the IP
you reference, and find I am already exempting them due to SPF.
Now SPF is admittedly a really lousy measure, but at least it's
*easy* to enable and cut out a lot of false-positive complaints.

My 2 cents.