How does Microsoft filter email?

Microsoft filters email through multiple layers of protection spanning their consumer services (Outlook.com, Hotmail) and business platforms (Office 365, Exchange Online). The filtering combines reputation assessment, content analysis, machine learning models, and user behavior signals.

At the first layer, Microsoft checks authentication (SPF, DKIM, DMARC) and sender reputation. Known bad actors get blocked immediately. Messages passing initial checks face content scanning by SmartScreen and related technologies that examine text, links, attachments, and sending patterns.

User engagement influences filtering for consumer accounts, with Microsoft tracking whether recipients interact positively or negatively with your messages. Business accounts add organizational policies through Exchange Online Protection, potentially layering additional filtering rules set by IT administrators.