Email Security.cloud Infrastructure Maintenance November 4-7, 2025

The scheduled maintenance is now underway. We'll keep you updated on our progress.

Broadcom is performing maintenance to the Email Security.cloud service beginning November 4 and ending November 7, 2025.

During this maintenance, Phase 1 of the new Anti-Echo-Spoofing Protection feature will be released. This functionality helps protect customers from attackers who use Microsoft 365 to send spoofed emails that impersonate their domains and relay them outbound through the Email Security.cloud service.

The Anti-EchoSpoofing service verifies that messages sent from Microsoft 365 tenants originate from an authorized organization. Messages sent from unrecognized or unauthorized tenants will be rejected at the time of delivery, reducing the risk of domain abuse and phishing. Administrators can view and manage authorized Microsoft 365 tenant identifiers in the Email Security.cloud Outbound Routes configuration for Microsoft 365.

NOTE: During Phase 1, Anti-EchoSpoofing protection will remain in Log-only mode to give customers visibility into which domains appear in the Microsoft X-OriginatorOrg headers within their organization. The new Microsoft 365 X-OriginatorOrg report will help customers to identify legitimate domains and mark them as allowed in preparation for enforcement in the next phase. Phase 2 support for enforcement is anticipated in late November.

Please refer to the September 2, 2025 release notes for details of the proactive measures and recommendations that we have implemented to combat EchoSpoofing.