Description
The Shield outbound relay is designed for human-to-human communication rather than for transactional messages, bulk mail, or mass mailing. Using the relay for transactional or high-volume sending can negatively affect the reputation of shared Shield outbound transport addresses, leading to delivery issues and potential blocklisting.
Outbound mail that exhibits this behavior, or other unhealthy sending patterns, may be flagged and temporarily held for review by Shield to help protect the deliverability of the shared transport environment. Organizations should use a dedicated email marketing platform for transactional or high-volume email distribution whenever possible.
If a third-party mailing platform is not an option, selectively routing those users outside of the Shield outbound connector so that mail is sent through Microsoft's outbound relay should be considered only as a last-resort alternative.
Applies to: Shield, Microsoft 365 (O365, M365)
Exclude a User from the Shield Outbound Connector
Sign in to the Microsoft 365 tenant for the Shield organization.
Go to Exchange > Mail Flow > Rules
Click on the name Shield - Send to Outpost, then click on Edit rule conditions.
For organizations added to Shield on or before January 31, 2025 the connector name may not be standardized. Look for a Shield outbound connector. If you are unsure which connector is the Shield outbound connector, please contact Support for assistance.
In the Except If section add The sender > Is this person > the email address to be routed around the Outbound connector. Save the change then Save the rule.
Allow up to one hour for the change to propagate from the Microsoft 365 tenant to their perimeter infrastructure, then test to ensure the exception is working as intended.
Once the user is added as an exception, Microsoft 365 will be the only protection for outgoing mail and Microsoft Message Trace will be the only location to view outbound mail sent by the user. Outbound mail sent by the user will continue to be visible in Spotlight for all messages sent before the exception was added.
Related to
Updated