Microsoft’s September 2026 SNDS portal update: what senders should know

The latest dated change: a new SNDS portal

The latest dated SNDS notice from Microsoft is marked “Last updated: September 22, 2026.” It welcomes users to a new SNDS portal, says it replaces the previous site, and flags an inaccurate deadline in the first network reattestation reminder. ^[1]

Microsoft says network access expires 10 months after approval or migration unless an authorized owner reattests it. Three reminder messages are sent at about three, six and nine months. The inaccurate date warning applies to the first reminder for migrated networks, so check the Access Control page rather than relying on that email’s displayed deadline. ^{[1] [2]}

This portal notice does not announce a new SNDS filter metric or JMRP complaint-process change. Microsoft’s Postmaster Services page still describes JMRP as reports on messages users mark as junk or phishing. We found no newer official JMRP change notice in the pages we reviewed. ^{[1] [3]}

What SNDS measures at the IP level

Smart Network Data Services gives an owner of sending IP space information about activity Microsoft sees from authorized IP addresses. It is a reputation and operational view of traffic to Outlook.com, not a complete report about your brand, every sending domain, or every mailbox provider. ^{[1] [2]}

The FAQ lists an activity period, SMTP command counts, message recipients, junk-filter results and complaint reports. It also describes records for virus-infected mail, malware hosting and open-proxy status. These signals can help identify unusual traffic, a poor recipient list or a compromised system, but they describe what happened at the IP rather than why every individual message was treated a certain way. ^[2]

Microsoft’s FAQ says activity is summarized by day, with the first and last hour shown. Data may take a few hours to appear and is retained for 90 days. Traffic or spam data may not appear for an IP that sent fewer than 100 messages that day, so a blank row does not prove that a sender has no deliverability problem. ^[2]

Read the colors and complaint rate carefully

SNDS reports aggregate spam-filter verdicts with green, yellow and red status. Microsoft’s FAQ defines green as under 10% spam verdicts, yellow as between 10% and 90%, and red as over 90%. Each recipient is counted as a verdict, so one message sent to several recipients contributes more than one result. ^[2]

Those colors are not an inbox-placement report. Microsoft explicitly says the filter result does not directly show deliveries to inbox or Junk folders, and user settings can change how a message is handled. Treat color as a useful signal about Microsoft’s aggregate filter assessment, then compare it with your own delivery logs and message-level outcomes. ^[2]

The FAQ defines complaint rate as complaints divided by message recipients. Complaint totals are assigned to the day users reported the message, not necessarily the day it arrived. That means a daily rate can exceed 100% when complaints reported that day refer to earlier messages. Do not read that figure as a simple same-day percentage of recipients. ^[2]

Microsoft’s published FAQ field list includes filter results and complaint reports, but it does not list a spam-trap-hit count. We could not confirm trap hits as a standard SNDS field in Microsoft’s public documentation, so check what your own portal shows before building a report or alert threshold around that number. ^[2]

How to request and keep access

Start with a Microsoft account, then request the IP address, range or autonomous system number for which you are responsible. Microsoft’s authorization process checks network information such as reverse DNS, RDAP records and routing data, then offers an authorization path tied to the network. You must complete that process before seeing the associated SNDS data. ^{[1] [2]}

The authorization process may not identify a contact you can use, especially if network records are incomplete or a request covers too much space. Microsoft’s FAQ recommends following the portal’s diagnostic guidance, trying a smaller range, or working with the network owner to correct the underlying records. An existing authorized owner can also approve another person’s access. ^[2]

Access is not permanent. The current FAQ says approved access lasts 10 months and must be reattested by an authorized network owner before expiry. Keep an owner responsible for renewals, review who has access, and check the portal’s current expiration date because the September notice says one reminder’s deadline display can be wrong. ^{[1] [2]}

Automating SNDS downloads

Microsoft’s FAQ describes two retrieval methods: browse the portal and export data as CSV, or enable an automated data URL for a system to retrieve the same data. The FAQ says that automated URL does not require a Microsoft-account sign-in when downloading the data, so treat the generated link as sensitive and limit where it is stored or shared. ^[2]

The public FAQ describes a data URL, not a REST API with OAuth credentials. We could not find a Microsoft-published OAuth or REST interface for SNDS, so use the method offered in your portal and avoid wiring production monitoring to an undocumented endpoint. ^[2]

What SNDS cannot replace: Outlook.com sender requirements

SNDS is scoped to the Outlook.com consumer service. Microsoft’s high-volume announcement specifically names outlook.com, hotmail.com and live.com consumer addresses; the Postmaster site is for professionals sending mail to Outlook.com. Do not treat an SNDS result as a universal score for Microsoft 365 or Exchange Online recipients. ^{[3] [5]}

For high-volume senders, Microsoft’s published policy says domains sending more than 5,000 messages per day to Outlook.com accounts must pass SPF and DKIM and publish DMARC at least at p=none, aligned with SPF or DKIM. Microsoft recommends alignment with both where possible. The policy says non-compliant mail goes to Junk and may be rejected if the issue remains unresolved. ^[4]

Microsoft’s April 2, 2025 Tech Community post, updated April 30, described the enforcement update: after initially discussing Junk-folder routing, Microsoft said it would reject messages that fail the stated authentication requirements starting May 5, 2025. The current Postmaster policy also summarizes the Junk action and possible rejection. Read the exact SMTP response and current policy when troubleshooting rather than assuming every failed message receives the same action. ^{[4] [5]}

The authentication rule is a requirement for the stated high-volume Outlook.com traffic. List hygiene, clear unsubscribe options and monitoring both SNDS and JMRP are practical sender practices, not extra SNDS fields. JMRP complements SNDS by returning message-level feedback for user reports, while SNDS helps show IP-level patterns. Neither service diagnoses every cause of filtering on its own. ^{[3] [4]}