DLP Prevents Microsoft 365 Copilot from Processing External Email

DLP Block to stop Copilot using external email.

A new (preview) DLP capability allows Microsoft 365 tenants to block Microsoft 365 Copilot from processing the content of external email. When set, any message coming from a domain that’s not in a tenant’s accepted domain list is blocked for Copilot for grounding, referencing, or summarization. It’s an effective way of blocking threat like prompt injections transmitted in email too, but some people might not like blocking all their external email.

Marking External Email with an Exchange Transport Rule

Helping Exchange Protect Users from Bad Email Given the amount of spam floating around today, it comes as no surprise that many organizations deploy an Exchange transport rule to mark inbound external email with a suitable warning. This is a straightforward rule to configure and it can help stop users being fooled by bad messages …