M365 Changelog: Blocking URLs and Files with Tenant Allow/Block List

MC237645 – Updated March 09, 2021: We have updated the rollout timeline below. Thank you for your patience.

We understand that, from time to time, you might disagree with an Exchange Online Protection (EOP) filtering verdict. With this update, you will be able to manually override Microsoft 365 filtering verdicts using the Tenant Allow/Block List (TABL) in the Security & Compliance Center.

This message is associated with Microsoft 365 Roadmap ID 61352.

When this will happen

We will roll this out from late February through early April (previously early March).

How this will affect your organization

Sometimes, a good message might be marked as bad (a false positive) or a bad message might be allowed through (a false negative). The first step is to report the message to Microsoft, preferably via the Admin Submissions portal. But if there is still a disagreement, tenants need to put in some kind of override, usually in the form of an Exchange Transport Rule (ETR). Although ETRs are robust enough to handle almost all scenarios, it is a complex manual process.

We are adding a Tenant Allow/Block List which EOP will use during mail flow and at the time of user clicks for files and URLs.

What you need to do to prepare

Initially, you will be able to block any URL or file (hash) for your tenant users.

• The function to allow will come at a later date.
• We also plan to expand Tenant Allow/Block List to eventually handle URLs, files, senders, and recipients. We will notify you of this additional functionality as it becomes available, via Message center.

Learn more: Manage the Tenant Allow/Block List