How to Enable and Use Exchange Online’s External Email Tagging Feature


Exchange Online tenants can activate external email tagging, which causes Outlook clients (not desktop yet) to highlight messages received from external domains. The feature can replace custom implementations to mark external email, usually done with transport rules. It’s easy to implement and control, but the mail tip offering to block an external sender seems a little over the top.

6 Replies

@Tony Redmond 


Is there a date set for enabling this feature in Outlook?

Haven't seen it turn up in a build yet,.

@Tony Redmond 


Thanks. I have this enabled for my clients since last year and it seems to work great in Outlook online and in the Outlook app. Not sure why its taking so long to enable the feature in Outlook. 

The nature of Outlook desktop is that it always takes longer to develop and implement UI than it does in OWA.

@Tony Redmond Do you know if there is there a way to change the layout of the tag in Outlook to make it stand out a little more?  Currently it has just the small exclamation point and the text "This sender xxx is from outside your organisation".  To really make it less subtile and have a better effect.


Best regards 

Jacob Christensen

I don't believe you can customize any aspect of the warning.