Microsoft SNDS
Smart Network Data Services (SNDS) is Microsoft's data service for senders who mail Outlook, Hotmail, and other Microsoft-hosted mailboxes. Microsoft's SNDS pages describe IP-level reputation, complaint rates, and trap hits.
Enrollment is tied to the IP addresses that send mail to Microsoft. It complements the SPF and DKIM records published in DNS; it does not replace them.
How operators use it
SNDS highlights when Microsoft sees high complaint volume or junk-folder placement from an IP range. Operators correlate those graphs with DMARC aggregate reports and their own bounce logs.
Microsoft Learn documents how to configure SPF and DKIM for mail sent from Microsoft 365. SNDS is telemetry about delivery to Microsoft recipients, not the configuration UI for those records.
Correlation
SNDS graphs help operators correlate complaint spikes with specific campaigns or IP ranges. Microsoft's FAQ describes enrollment and data retention for enrolled IPs.
DNS authentication for mail sent from Microsoft 365 is still documented on Microsoft Learn. SNDS does not publish SPF or DKIM strings for the tenant.
Operators who send through Microsoft 365 and through other SMTP paths may need both SNDS enrollment for their dedicated IPs and the provider pages for DNS authentication records.