Most RecentMost ViewedMost LikesExchange Online canceling the Mailbox External Recipient Rate Limit The Mailbox External Recipient Rate Limit in Exchange Online is being canceled. Exchange Online to introduce External Recipient Rate Limit Today, we are announcing that, beginning in January 2025, Exchange Online will begin enforcing an external recipient rate limit of 2000 recipients in 24 hours. High Volume Email: Continued support for Basic Authentication & other important updates This announcement provides several important updates for High Volume Email. Introducing more control over Direct Send in Exchange Online Read about a new feature that gives you more control over Direct Send in Exchange Online. Announcing General Availability (GA) of the New Message Trace in Exchange Online We are excited to announce the GA of the new Message Trace in the Exchange admin center (EAC) in Exchange Online. Introducing Exchange Online Tenant Outbound Email Limits We’re introducing new tenant-level outbound email limits (also known as the Tenant External Recipient Rate Limit or TERRL). Exchange Online to retire Basic auth for Client Submission (SMTP AUTH) Today, we are announcing that Exchange Online will permanently remove support for Basic authentication with Client Submission (SMTP AUTH) starting March 2026. Limiting Onmicrosoft Domain Usage for Sending Emails We are announcing that all Exchange Online customers who send external email should start switching to custom (aka vanity) domain names. Demystifying Centralized Mail Transport and Criteria Based Routing Today we wanted to cover Centralized Mail Transport (CMT) and Criteria Based Routing (CBR). Direct Send vs sending directly to an Exchange Online tenant This post discusses what Direct Send is, is not, and how to help control email sent directly to your tenant.
