If you start to see 4xx deferrals (esp. 3113, 3114, 3115, 3150, …) from the “Hotmail/Outlook/et al” data centers, you should know that the IP has been throttled, and one would be well advised, given that situation, to STOP all sending until at least the top of the hour, plus a few minutes. And if the deferrals continue with THAT traffic, it is strongly suggested that one hold off on any sending from that IP for at least 24 hours. Bottom line is, right now, if you start seeing 4xx deferrals from “HotMail” on a given IP, you should stop sending immediately if you at all possibly can as it may affect the IP’s reputation. But in general, if when you connect to a given mail server, all you are seeing is deferrals, you should 1) notice, and 2) back off.
And you should do some navel gazing to make sure those deferrals were not happening for an as-of-yet un-noticed cause. Aloha, Michael. -- Michael J Wise Microsoft Corporation| Spam Analysis "Your Spam Specimen Has Been Processed." Got the Junk Mail Reporting Tool<http://www.microsoft.com/en-us/download/details.aspx?id=18275> ? -----Original Message----- From: mailop <mailop-boun...@mailop.org> On Behalf Of Johann Klasek Sent: Thursday, June 28, 2018 2:19 AM To: mailop@mailop.org Subject: Re: [mailop] Recent "banned sending IP" errors when sending to Microsoft On Thu, Jun 28, 2018 at 12:47:13AM -0500, Michael Rathbun wrote: > On Wed, 27 Jun 2018 20:42:16 +0000, Michael Wise via mailop > <mailop@mailop.org<mailto:mailop@mailop.org>> wrote: > > > > >Office365 and Hotmail/Outlook/Live/MSN are very much distinct systems, > >even thought they are now running on the same hardware. > >Sort of like BASH vs TCSH. > > Given an episode where a client is seeing the "unfortunately not > delivered because network is on our blocklist" 55x message for hotmail > delivery attempts, while SNDS tells them that the IP is not blocked, I > suspect that there may be some aspects of the melded infrastructure > wherein the right hand still doesn't even suspect that a left hand exists. Same here, one of our main student mail server is currently blocked. Very irritating and unhelpful that this is not shown on SNDS. > We are waiting to see whether the ticket response is the "you aren't blocked" > message, but it's been a while since they submitted the form and they > haven't seen a reply other than the auto-ack yet. Still waiting too ... Johann TU Wien _______________________________________________ mailop mailing list mailop@mailop.org<mailto:mailop@mailop.org> https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fchilli.nosignal.org%2Fcgi-bin%2Fmailman%2Flistinfo%2Fmailop&data=02%7C01%7Cmichael.wise%40microsoft.com%7C3d6930ec773b4c5ec54508d5dcd9c9fb%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636657750318147346&sdata=rWov3uybafM8G3kXcCNDRzinh6g8CkrGL%2B821n5zCsA%3D&reserved=0
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