MSFT reverse IP failure?

Jeff Mealiffe jeffmeal at
Mon Feb 26 22:46:55 UTC 2018

Which "Exchange tools site" are you referring to?

Happy to help get this fixed up.


-----Original Message-----
From: NANOG <nanog-bounces at> On Behalf Of Ken Chase
Sent: Monday, February 26, 2018 1:31 PM
To: nanog at
Subject: Re: MSFT reverse IP failure?

Having a client doing a test from the MSFT exchange tools site, which is failing.

NOQUEUE: reject: RCPT from unknown[]: 450 4.7.1 Client host rejected: cannot find your reverse hostname, [];

NetRange: -
CIDR: ,,
NetName:        MSFT

A bit of an oversight?

Ken Chase - math at Guelph Canada

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