Microsoft – incompetent or malicious?

A couple of days before christmas, mail sent from my mail server to people hosting their mail in the MS Office365 platform started bouncing:

<>: host[] said:                                                                                                                       
    550 5.7.511 Access denied, banned sender[X.X.X.X]. To request                                                                                                                            
    removal from this list please forward this message to                                                                                                                                        For more information please go to                                                                                                                            AS(1410)                                                                                                                                          
    [] (in reply to RCPT TO                                                                                                                       

So, first response is of course to do as told. Sending a mail to gives zero useful answer at all. Starting to think that I can get through by improving my mail security – perhaps they have imposed some new rules – I check and correct SPF, and configure DKIM. This again gave zero useful result – but I guess I should thank Microsoft for causing me to look into this again 🙂

After some more checking, I discovered: It’s not me, it’s them. Seems my server is collateral damage in MS blacklisting a couple of pretty large netblocks.

There’s a couple of threads on the Internet about this, here’s a few. Read through them and weep.

Now, Microsoft is a serious company, so of course they have a service you can mail, and report that you’ve been blocked erroneously. Upon doing so, I get back:

Not qualified for mitigation                                                                                                                                                                         
Our investigation has determined that the above IP(s) do not qualify                                                                                                                                 
for mitigation.                                                                                                                                                                                      
Please ensure your emails comply with the policies,                                                                                                                                      
practices and guidelines found here:                                                                                                                                                                                                                                                                                                                     

I’ve personally tried reporting this as a mistake to MS a couple of ways. Their systems apparently doesn’t have any record of the blocking. One of the mails I get back tells me I can reply if I need more information and that is an error. And on doing so…it bounces, because I’m blocked!

Taking it a step further, I try postmaster and abuse. Both of them causes the mail to bounce. Great.

Now, replying to this, I actually get reply from someone. «Thank god», I thought. A human.

But I was too quick. A couple of weeks later, my case is going nowhere. And neither is the case of anyone else. There’s various people that have had limited success by having the complaint sent via support for the office365 system as a customer, and even signing up for one specifically for that purpose. But having no company to register under, that’s not an option for me.

So, I ask myself – is the days where you could host your own mail gone? Are we at the mercy of large companies of Microsoft? Can a large provider block the networks of hosting providers just like that, without the world calling them out? It’s pretty clear to me that if you’re not a Microsoft customer, your requests does not come high up on the priority list.

But, I can’t help wonder – if you are a customer running your mail hosted in Office365 – do you have problems with some of your customers mail not getting to you? If so, here’s the answer. Microsoft doesn’t care whether or not non-Microsoft customers can send mail to their customers. If they did, they’d have solved this issue weeks ago.

2 kommentarer

  1. welcome to the internet.. my german hoster has a ton of threads about microsoft simply blackholing whole ip ranges if they don’t like you

    1. I know, but that doesn’t mean I have to accept it. We should continue to call them out on it, and make sure that the likelihood that people having MS-hosted accounts know that they are missing legitimate mails increases.

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