How to interpret Microsoft SNDS data?

You log into Outlook's Smart Network Data Services (SNDS) and see a yellow traffic light next to your sending IP. Is that a warning you can ignore, or something that needs fixing today? Once you know what each signal actually means, the answer becomes pretty obvious.

SNDS gives you IP-level reputation data for Outlook, Hotmail, and Live.com. Microsoft still weighs IP reputation heavily in its filtering decisions, which makes SNDS one of the more useful free tools available to senders.

The traffic lights

Green means your IP is in good standing. Microsoft isn't seeing anything alarming from it. Yellow means something triggered concern. That could be a spike in complaints, a spam trap hit, or a temporary pattern Microsoft doesn't like. It's not a disaster, but it's not something to sit on either. Red means Microsoft has flagged your IP for active filtering. Emails from that IP are likely being blocked or sent to junk automatically. Red needs attention now, not later.

Complaint rates

This is the percentage of recipients who clicked "Report Junk" on your mail. Keep this below 0.1%. If you're sitting at 0.08%, you're within safe range, but you're close enough to the edge that one bad campaign could push you over. If you're already above 0.1%, that's a real signal that something in your sending is frustrating recipients. (And yes, even unengaged subscribers who forget they signed up will eventually hit that button.)

Spam trap hits

SNDS shows whether you're hitting Microsoft's trap network. A spam trap is an address that no real person uses. If mail is going there, it means your list has a hygiene problem. Even a small number of trap hits can turn a green light yellow or a yellow light red. Trap hits are often worse than complaint rates because they signal you're sending to addresses you never should have had.

Sample data

SNDS shows you a sample of messages that generated complaints. Pull this data when you're trying to identify which campaign or segment triggered a spike. Look at the subject lines, the send times, and which IP or range the complaints came from. You'll usually find one culprit campaign or one poorly-segmented audience.

What to actually do with it

Yellow light with complaint rate under 0.1% and no trap hits: monitor it weekly, look at what you sent recently, and tighten your list hygiene. Yellow light with trap hits: stop sending from that IP until you've cleaned the list. Red light: file a mitigation request through Microsoft's support portal and pause sending from that IP while you investigate. Don't just wait for it to clear on its own.

Worth noting: SNDS is IP-level only. If you want to understand how your domain reputation looks to Microsoft, that's a different conversation. The difference between IP and domain reputation in SNDS is worth reading next if you're not clear on why both matter.

Still if your IP is already red and you're not sure where to start, reach out on our SOS hotline. It's free and we'll help you figure out the right steps without the guesswork.