check before: 2025-08-01
Product:
Defender, Defender for Office 365, Defender XDR, Entra, Microsoft 365 admin center, Purview, Purview Communication Compliance, Teams
Platform:
Online, Web, World tenant
Status:
In development
Change type:
Admin impact, New feature, Updated message, User impact
Links:
Details:
Summary:
Microsoft Teams now integrates with Microsoft Defender for Office 365 Tenant Allow/Block List, enabling security admins to centrally block external domains in Teams. This feature, rolling out January 2026, allows managing blocked domains, preventing communications, deleting existing messages, and auditing actions, with admin controls via Teams and Entra ID.
Details:
Updated November 17, 2025: We have updated the timeline. Thank you for your patience.
Introduction
We're introducing a new integration between Microsoft Teams and Microsoft Defender for Office 365 that enables security admins to manage blocked external domains in Teams using the Tenant Allow/Block List (TABL) in the Microsoft Defender portal. This feature enhances security by allowing organizations to centrally manage domain blocks across Microsoft 365 services.
This capability is available to customers with Microsoft Defender for Office 365 Plan 1 or Plan 2 and Microsoft Teams.
This message is associated with Microsoft 365 Roadmap ID 492985.
When this will happen
Targeted Release: We will begin rolling out late August 2025 and expect to complete by early September 2025.
General Availability (Worldwide): We will begin rolling out early January 2026 (previously late September 2025) and expect to complete by end of January 2026 (previously early October 2025).
Change Category:
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Scope:
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Release Phase:
General Availability, Targeted Release
Created:
2025-08-12
updated:
2025-11-18
Task Type
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Docu to Check
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MS How does it affect me
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MS Preperations
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MS Urgency
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MS workload name
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linked item details
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Pictures
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summary for non-techies**
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Direct effects for Operations**
Blocked Communications
If the change is implemented without preparation, users may experience unexpected blocking of communications from legitimate external domains, leading to disruptions in collaboration and communication.
- roles: Security Admin, Teams Admin
- references: https://learn.microsoft.com/defender-office-365/tenant-allow-block-list-teams-domains-configure, https://www.microsoft.com/microsoft-365/roadmap?filters=&searchterms=492985
User Experience Degradation
Users may face a degraded experience due to the sudden removal of access to external communications, which can hinder productivity and lead to frustration among team members.
- roles: End User, Teams Admin
- references: https://learn.microsoft.com/defender-office-365/tenant-allow-block-list-teams-domains-configure, https://www.microsoft.com/microsoft-365/roadmap?filters=&searchterms=492985
Compliance Monitoring Challenges
Without proper preparation, the new audit logs may not be effectively utilized, leading to challenges in compliance monitoring and reporting for actions taken on blocked domains.
- roles: Compliance Officer, Security Admin
- references: https://learn.microsoft.com/defender-office-365/tenant-allow-block-list-teams-domains-configure, https://www.microsoft.com/microsoft-365/roadmap?filters=&searchterms=492985
Configutation Options**
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Opportunities**
Centralized Domain Management
The integration allows security admins to manage blocked domains centrally across Microsoft Teams, enhancing security and simplifying administrative tasks. This can lead to a more streamlined user experience by reducing the risk of phishing and other security threats from external domains.
- next-steps: Review current domain management practices and align them with the new integration capabilities. Train security and Teams admins on how to utilize the Tenant Allow/Block List effectively.
- roles: Security Admins, Teams Admins, Compliance Officers
- references: https://learn.microsoft.com/defender-office-365/tenant-allow-block-list-teams-domains-configure, https://www.microsoft.com/microsoft-365/roadmap?filters=&searchterms=492985
Enhanced Compliance Monitoring
With the new audit logs generated for actions taken on blocked domains, organizations can improve their compliance monitoring and reporting capabilities. This can facilitate easier compliance audits and enhance overall governance.
- next-steps: Integrate audit log reviews into regular compliance checks and ensure relevant teams are trained on accessing and interpreting these logs.
- roles: Compliance Officers, Security Admins, IT Auditors
- references: https://learn.microsoft.com/defender-office-365/tenant-allow-block-list-teams-domains-configure, https://www.microsoft.com/microsoft-365/roadmap?filters=&searchterms=492985
Improved User Experience
By allowing security admins to delete existing communications from blocked domains, the integration can significantly enhance user experience by reducing exposure to potentially harmful content and improving the overall security posture.
- next-steps: Communicate the changes to users and provide guidance on the implications of blocked domains in their communications. Gather feedback on user experience post-implementation to make further improvements.
- roles: End Users, Teams Admins, Security Admins
- references: https://learn.microsoft.com/defender-office-365/tenant-allow-block-list-teams-domains-configure, https://www.microsoft.com/microsoft-365/roadmap?filters=&searchterms=492985
Potentional Risks**
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Data Protection**
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IT Security**
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Hypothetical Work Council Statement**
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DPIA Draft**
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explanation for non-techies**
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** AI generated content. This information must be reviewed before use.
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change history
| Date | Property | old | new |
| 2025-11-18 | MC Last Updated | 08/22/2025 20:34:04 | 2025-11-17T18:26:51Z |
| 2025-11-18 | MC Messages | Updated August 22, 2025: We have updated the timeline. Thank you for your patience.
Introduction We're introducing a new integration between Microsoft Teams and Microsoft Defender for Office 365 that enables security admins to manage blocked external domains in Teams using the Tenant Allow/Block List (TABL) in the Microsoft Defender portal. This feature enhances security by allowing organizations to centrally manage domain blocks across Microsoft 365 services. This capability is available to customers with Microsoft Defender for Office 365 Plan 1 or Plan 2 and Microsoft Teams. This message is associated with Microsoft 365 Roadmap ID 492985. When this will happen Targeted Release: We will begin rolling out late August 2025 and expect to complete by early September 2025. General Availability (Worldwide): We will begin rolling out late September 2025 and expect to complete by early October 2025. | Updated November 17, 2025: We have updated the timeline. Thank you for your patience.
Introduction We're introducing a new integration between Microsoft Teams and Microsoft Defender for Office 365 that enables security admins to manage blocked external domains in Teams using the Tenant Allow/Block List (TABL) in the Microsoft Defender portal. This feature enhances security by allowing organizations to centrally manage domain blocks across Microsoft 365 services. This capability is available to customers with Microsoft Defender for Office 365 Plan 1 or Plan 2 and Microsoft Teams. This message is associated with Microsoft 365 Roadmap ID 492985. When this will happen Targeted Release: We will begin rolling out late August 2025 and expect to complete by early September 2025. General Availability (Worldwide): We will begin rolling out early January 2026 (previously late September 2025) and expect to complete by end of January 2026 (previously early October 2025). |
| 2025-11-18 | MC End Time | 12/08/2025 08:00:00 | 2026-03-02T08:00:00Z |
| 2025-11-18 | MC Summary | Microsoft Teams now integrates with Microsoft Defender for Office 365 Tenant Allow/Block List, enabling security admins to centrally manage blocked external domains in Teams. This feature, rolling out from August to October 2025, allows blocking communications, deleting existing messages, and auditing actions, with admin controls managed via Teams and Entra ID. | Microsoft Teams now integrates with Microsoft Defender for Office 365 Tenant Allow/Block List, enabling security admins to centrally block external domains in Teams. This feature, rolling out January 2026, allows managing blocked domains, preventing communications, deleting existing messages, and auditing actions, with admin controls via Teams and Entra ID. |
| 2025-08-23 | MC MessageTagNames | New feature, User impact, Admin impact | Updated message, New feature, User impact, Admin impact |
| 2025-08-23 | MC Summary | Microsoft Teams now integrates with Microsoft Defender for Office 365 Tenant Allow/Block List, enabling security admins to centrally manage blocked external domains in Teams. This blocks communications from those domains, supports audit logging, and requires Teams admins to enable security team access. Rollout begins mid-August 2025. | Microsoft Teams now integrates with Microsoft Defender for Office 365 Tenant Allow/Block List, enabling security admins to centrally manage blocked external domains in Teams. This feature, rolling out from August to October 2025, allows blocking communications, deleting existing messages, and auditing actions, with admin controls managed via Teams and Entra ID. |
| 2025-08-23 | MC Last Updated | 08/12/2025 01:32:01 | 2025-08-22T20:34:04Z |
| 2025-08-23 | MC Messages | Introduction
We're introducing a new integration between Microsoft Teams and Microsoft Defender for Office 365 that enables security admins to manage blocked external domains in Teams using the Tenant Allow/Block List (TABL) in the Microsoft Defender portal. This feature enhances security by allowing organizations to centrally manage domain blocks across Microsoft 365 services. This capability is available to customers with Microsoft Defender for Office 365 Plan 1 or Plan 2 and Microsoft Teams. This message is associated with Microsoft 365 Roadmap ID 492985. When this will happen Targeted Release: We will begin rolling out in mid-August 2025 and expect to complete by mid-September 2025. General Availability (Worldwide): We will begin rolling out mid-September 2025 and expect to complete by late September 2025. | Updated August 22, 2025: We have updated the timeline. Thank you for your patience.
Introduction We're introducing a new integration between Microsoft Teams and Microsoft Defender for Office 365 that enables security admins to manage blocked external domains in Teams using the Tenant Allow/Block List (TABL) in the Microsoft Defender portal. This feature enhances security by allowing organizations to centrally manage domain blocks across Microsoft 365 services. This capability is available to customers with Microsoft Defender for Office 365 Plan 1 or Plan 2 and Microsoft Teams. This message is associated with Microsoft 365 Roadmap ID 492985. When this will happen Targeted Release: We will begin rolling out late August 2025 and expect to complete by early September 2025. General Availability (Worldwide): We will begin rolling out late September 2025 and expect to complete by early October 2025. |
| 2025-08-23 | MC Title | Microsoft Teams Integration with Microsoft Defender for Office Tenant Allow/Block List for blocking domains | (Updated) Microsoft Teams Integration with Microsoft Defender for Office Tenant Allow/Block List for blocking domains |
| 2025-08-23 | MC End Time | 10/31/2025 08:00:00 | 2025-12-08T08:00:00Z |
Last updated 3 weeks ago ago
