EMail server gets blocked by Microsoft

Mike Hammett nanog at
Wed Apr 28 11:51:40 UTC 2021

Neither Microsoft nor Google have been successful at making tools that work for low-volume mailers. They seem to think that if you're not in their club, you're either a commercial email marketing firm or SPAM. 

Mike Hammett 
Intelligent Computing Solutions 

Midwest Internet Exchange 

The Brothers WISP 

----- Original Message -----

From: "Michael Fallen" <mikefallensignup at> 
To: "Dominque Roux" <dominique.roux at> 
Cc: nanog at 
Sent: Tuesday, April 27, 2021 9:22:29 AM 
Subject: Re: EMail server gets blocked by Microsoft 

Microsoft seems to be one of the worst offenders in terms of having a 
email blocking blackbox. Good luck getting in contact with someone as 
well. Throughout the years of self-hosting email they have always been 
the most problematic of the large providers. 


Dominque Roux wrote on 2021-04-27 3:35 AM: 
> Hi All, 
> is there anyone out there who has some experience with the blocking 
> mechanism of Microsofts mail server? We're running a mail server at our 
> company which ends up on their blacklist from time to time and we're 
> wondering if there are some steps we could take in order to prevent this. 
> Cheers, 
> Dominique 

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