Learn how to prepare your email environment for the permanent retirement of SMTP auth in Exchange online by September 2025.

Learn how to configure High Volume Email in Microsoft 365 to increase the Exchange Online messaging limits for your applications.

Learn about the High Volume Email service in Microsoft 365's Exchange Online platform so send bulk emails to external recipients.

Learn how to block an email address or Domain for all users in Exchange Online using the Microsoft 365 defender portal.

Learn how to modify how Microsoft 365 handles DMARC for inbound mail with DMARC policies in Microsoft Defender.