Security Architecture Overview: microsoft.com
Microsoft.com employs an enterprise multi-tier SPF architecture alongside strict DMARC p=reject enforcement. Outbound communications from Exchange Online and corporate infrastructure are cryptographically signed with dual-rotating DKIM keys.
Key Anti-Spoofing & Cryptographic Highlights
Frequently Asked Questions
What is Microsoft's SPF configuration?
Microsoft splits its sending ranges across modular sub-records including _spf-a.microsoft.com and _spf-b.microsoft.com with a -all hardfail policy.