If you’ve already added your Microsoft SNDS Key(s) to your HetrixTools account, as explained in our documentation here, then you might have already noticed that 3 new blacklists have appeared in your Blacklist Reports:

  • Microsoft SNDS Yellow
  • Microsoft SNDS Red
  • Microsoft SNDS Blocklist

In this article we’ll explain what each of these lists actually mean.

Let’s start off with the Yellow and Red lists:

If your IP is listed on the Yellow or on the Red lists it doesn’t necessarily mean that Microsoft is blocking the traffic from your IP, but that your IP has the ‘Yellow’ or (even worse) ‘Red’ status on their system, as explained in their F.A.Q. here:
https://sendersupport.olc.protection.outlook.com/snds/FAQ.aspx#filterResult

This should be enough reason for concern, because even though your traffic isn’t completely blocked yet, Microsoft is still filtering out (ie: blocking) a lot of the traffic coming from your IP address.

Yellow meaning they’ve detected between 10% and 90% spam coming from your IP address.

Red meaning they’ve detected more than 90% spam coming from your IP address.

These 2 lists, on the HetrixTools platform, should be carefully monitored because they are clear indicators that your IP is heading in the wrong direction, and that it may soon get on the blocklist.

The Blocklist

This list is pretty straight forward. If your IP appears on this list then Microsoft SNDS has already blocked your IP address completely.

You can see further details about the listing as described in our documentation, here:
https://docs.hetrixtools.com/view-further-blacklisting-details-in-your-reports/

In order to get your IP unblocked from the Microsoft SNDS Blocklist, you will need to follow the steps listed here:
https://docs.hetrixtools.com/how-to-remove-your-ip-from-the-outlook-blacklist/