External Auto-Forwarding

Question

Where specifically in Exchange Online would it list if the administrator has put restrictions in place to block external auto-forwarding of messages? e.g. Is it best achieved via transport rules?

Answer 1

The outbound SPAM rule: https://learn.microsoft.com/en-us/microsoft-365/security/office-365-security/outbound-spam-policies-external-email-forwarding?view=o365-worldwide#how-the-outbound-spam-filter-policy-settings-work-with-other-automatic-email-forwarding-controls or a transport rule. https://techcommunity.microsoft.com/t5/exchange-team-blog/the-many-ways-to-block-automatic-email-forwarding-in-exchange/ba-p/607579 There is not best way, however if you do not need to autoforward, I would block via the outbound SPAM policy. IF you need to allow some auto forwarding, use a transport rule that blocks all auto forwards except those allowed senders or recipients.