492985 – Microsoft Teams integration with Microsoft Defender for Office Tenant/Allow Block List for domains

Product:

Defender, Defender for Office 365, Teams

Platform:

Web, World tenant

Status:

Launched

Change type:

Links:

MC1133508

Details:

Security and IT admins can increase domain-level control with the Tenant Allow/Block List feature in the Microsoft Defender portal to block domains for Microsoft Teams. This post was published previously with incorrect information and has been corrected. We apologize for the inconvenience.

Change Category:
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Scope:
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Release Phase:
General Availability, Targeted Release

Created:
2025-05-15

updated:
2025-12-18

Docu to Check

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MS workload name

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summary for non-techies**

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Direct effects for Operations**

Please, look at the most relevant linked item for details

explanation for non-techies**

Imagine your office as a large building with multiple rooms, each representing different departments like HR, Legal, and Management. Now, think of Microsoft Teams as the hallways and meeting rooms that connect these departments, allowing everyone to communicate and collaborate efficiently.

In this building, security is crucial to ensure that only authorized individuals can enter and move around freely. This is where Microsoft Defender for Office 365 comes into play. It's like the security team that monitors who comes in and out of the building, ensuring that everyone inside is safe from potential threats.

The Tenant Allow/Block List feature is like a guest list at the entrance. Security admins can decide which domains (or "guests") are allowed to enter the building and which are not. By integrating this feature with Microsoft Teams, admins can block certain domains from interacting with your Teams environment. This is similar to preventing unwanted visitors from entering the building, ensuring that only trusted guests can participate in conversations and share information.

For example, if your company receives a lot of spam or phishing attempts from a particular domain, the security team can add that domain to the block list. This action prevents any communication from that domain from reaching your Teams environment, much like a security guard stopping an unwanted guest at the door.

In summary, this integration helps maintain a secure and efficient communication environment within Microsoft Teams by allowing security admins to control which external domains can interact with your organization. It's a proactive measure to protect your company's digital workspace, much like a vigilant security team safeguarding a physical office building.