Microsoft SNDS and JMRP explained
Smart Network Data Services (SNDS) and the Junk Mail Reporting Program (JMRP) are Microsoft's two free tools for people who send mail to Outlook.com, Hotmail and Live addresses. SNDS shows, per sending IP address, how much mail Outlook.com received, what share its filters judged to be spam and how often users complained. JMRP sends you a report each time an Outlook.com user marks one of your messages as junk, so you can stop mailing that person. Both work by IP address, so they are most useful when you control your own sending IPs; on a shared pool, your email service provider usually holds the access.
What changed in 2026
Microsoft moved SNDS to a new portal. The old address on sendersupport.olc.protection.outlook.com now redirects to the new SNDS site, which says it replaces the previous one. You sign in with a Microsoft account, and the portal states that network access expires 10 months after approval or migration unless you reattest that you still own the addresses. Reminders arrive about 3, 6 and 9 months after approval (SNDS FAQ).
The data changed too. The current FAQ lists no trap-hit column. The industry site emailexpert reported that Microsoft removed spam trap hit counts from SNDS from 22 July 2026, so older tutorials that tell you to watch trap hits there are out of date. JMRP reports changed as well (see what a report contains).
If you set SNDS or JMRP up before 2026, log in to the new portal and check that your networks and feeds are still there.
Who can use them
SNDS is open to anyone who can show they control an IP range. It does not work by domain. The FAQ describes three ways the portal finds an address that may approve your request:
- Reverse DNS. If the host names in the range share a domain, it offers
postmaster@andabuse@at that domain. It samples only ranges of /23 or smaller. - RDAP. It reads the registry record for the range and offers the contacts listed there.
- ASN. For an autonomous system number, it uses the ASN record and covers the subnets that ASN announces.
You pick one of the offered addresses, receive a link there and click it. Microsoft does not process manual requests. Someone who already has access can also delegate it to you.
That model decides who can join:
| Your setup | Can you use SNDS and JMRP yourself? |
|---|---|
| Your own mail servers on your own IPs | Yes: request the range. |
| Dedicated IPs at an email service provider | Possibly: the provider can delegate access, or you can request the IPs yourself if their reverse DNS uses a domain you control. Ask the provider. |
| A shared IP pool | Usually not. The provider holds the access. The FAQ adds that on a shared IP, JMRP complaint counts include every domain sending from it. |
If you are deciding between the two models, see shared vs dedicated IPs. Valid reverse DNS helps here as well as with delivery: Microsoft's Postmaster policies require it for sending servers (reverse DNS and PTR records).
What SNDS shows
For each IP and day, the SNDS FAQ lists:
- Activity period: the first and last hour, in Pacific time, in which the IP sent mail. IPs that sent fewer than 100 messages that day may show no traffic or spam data.
- RCPT and DATA commands: how many recipients the IP asked for and how many messages it transmitted.
- Message recipients: recipients on messages actually sent. A large gap between this and the RCPT count can point to a problem.
- Filter result: a color based on the share of recipients whose message Outlook.com's filters judged to be spam.
- Complaint rate: complaints divided by message recipients.
- Comments: JMRP complaint details, virus detections, malware hosting and open proxy findings.
Filter result colors
| Color | Share judged as spam |
|---|---|
| Green | below 10% |
| Yellow | between 10% and 90% |
| Red | above 90% |
The FAQ warns that the color is not a measure of inbox or junk folder placement. Green does not mean you reach the inbox.
Complaint rate
The complaint rate is the share of messages from the IP that users reported. Complaints count on the day they are made, not the day you sent, so a quiet day after a large send can show a rate above 100%. The FAQ also notes that the indicators need not agree with each other: mail that is filtered reaches fewer inboxes and so draws fewer complaints, which can make a struggling IP look calm.
Microsoft publishes no complaint threshold. Its Postmaster troubleshooting page names the junk complaint rate as one of the main factors that drive a sender's reputation down.
IP status
The View IP Status page lists your IPs that Outlook.com currently treats as blocked, as showing bot-like behavior, or as junked. It covers the last 24 hours only, keeps no history and is not real time. Daily data is processed from about midnight Pacific time, can take a couple of hours, and stays available for 90 days. You can export it as CSV or fetch it through an automated access link.
What JMRP sends
JMRP is Microsoft's complaint feedback loop. Microsoft's Postmaster services page describes it as a free program that returns selected headers of messages Outlook.com users mark as junk, and says feedback can start within 72 hours of enrolling. Enrollment runs inside the SNDS portal, on its Junk Mail Reporting Program page, after you sign in. Microsoft's pages also call it the Junk Email Reporting Program; it is the same service.
What a report contains
Each report is a message in the Abuse Reporting Format, the standard format for complaint reports (see email feedback loops). Spam Resource quoted a notice on the old SNDS site saying that all JMRP feeds are now in ARF, that complaint sample downloads were discontinued, and that reports would carry only the original headers and selected authentication headers, without the message body. The same notice said JMRP feeds not linked to an SNDS account would be removed.
Practitioners report that the recipient's address is now hidden as well. emailexpert described reports from mid June 2026 in which the To: header is replaced by a placeholder and the header that used to carry the complainer's address is gone, while the Message-ID survives. Microsoft's own pages do not describe the format in that detail, so build your processing on what you receive.
What to do with JMRP reports
- Make every message traceable. Since the address may be hidden, put your own identifier for the recipient and campaign into the
Message-IDor a custom header when you send. RFC 6449, section 4.4, recommends exactly this for feedback loops that redact addresses. Do not format the identifier as an email address. - Suppress the complainer at once. Treat a report like an unsubscribe for that list, and add the address to your suppression list so an import cannot bring it back.
- Look for the source. Group reports by campaign, list and sign-up source. A spike from new subscribers points at how addresses were collected; a spike from long-time subscribers points at a particular message or frequency.
- Keep the enrollment current. Microsoft's troubleshooting page asks senders to update their JMRP enrollment when they add IPs.
The general method, with the report format, is in email feedback loops.
How this ties to Outlook.com's sender rules
Since 2025, domains that send more than 5,000 messages a day to Outlook.com must pass SPF, DKIM and DMARC, or their mail can be rejected with 550 5.7.515 (Outlook sender requirements). Those rules are about your domain. SNDS and JMRP are about your IPs. Authentication proves the mail is yours; SNDS and JMRP show whether Outlook.com users want it.
In practice:
- Before a large send, check that recent days show green and a low complaint rate for every sending IP.
- When mail starts going to junk, look at the IP status page and the complaint trend before you change content. The Policies page also asks you not to retry addresses that returned a permanent error, and to stop mailing a recipient after repeated non-delivery reports.
- On new IPs, SNDS lets you watch reputation build during warm-up.
Questions
Is SNDS Microsoft's version of Google Postmaster Tools?
In purpose, yes; in design, no. SNDS reports per IP address and needs proof that you own the range. Google Postmaster Tools reports per domain, verified through DNS.
Does SNDS cover Microsoft 365 business mailboxes?
Microsoft describes SNDS and JMRP in terms of Outlook.com and its users. Business mailboxes on Microsoft 365 are filtered separately and return their own codes, such as 5.7.606.
Why does SNDS show green while my mail lands in junk?
The color only reflects the share of mail judged as spam, and the FAQ says it does not measure inbox placement. Check the complaint rate, the IP status page and your domain's authentication too.
Can SNDS get my IP delisted?
No. The FAQ says the SNDS team does not handle delivery requests; it points you to Outlook.com's sender support.
Try it
Complaints and junk placement often start with old or unconfirmed addresses. Check a list with bulk email verification before a large send, or try one address in the free email checker.
Related
- The valid status: frequent complainers and why complaints hurt.
- Glossary: sender reputation.
- Bounce code 550 5.5.0: an Outlook.com address that does not exist.
Related guides
- Outlook.com requirements for high-volume senders
- Email feedback loops explained
- Shared vs dedicated sending IPs
- Sender reputation explained
- How to use Google Postmaster Tools
- All guides
Sources
- Microsoft: Smart Network Data Services: the new portal, Microsoft account sign-in, 10-month access expiry.
- Microsoft: SNDS FAQ: sign-up and authorization, data fields, filter colors, complaint rate, IP status, data timing and retention, shared IPs.
- Microsoft: Postmaster services for senders and ISPs: what SNDS and JMRP are, 72 hours to first feedback.
- Microsoft: Postmaster policies, practices and guidelines: reverse DNS, permanent failures, high-volume authentication rules.
- Microsoft: Postmaster troubleshooting: complaint rate as a reputation factor, keeping JMRP current.
- Spam Resource: January 2026 Microsoft SNDS updates: the SNDS notice on ARF, discontinued samples and reduced report content.
- emailexpert: Microsoft redacts JMRP (18 June 2026): observed redaction of the recipient address.
- emailexpert: Microsoft removes trap-hit data from SNDS (23 July 2026): removal of trap-hit counts.
- RFC 6449, Complaint Feedback Loop Operational Recommendations: section 4.4 on identifiers in redacted reports.
How we wrote this: drafted by the email-validation.org team with the help of AI writing tools, from our product documentation and the sources linked in the text.