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:
Launched
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 manage blocked external domains in Teams. This feature, available with Defender Plan 1 or 2, blocks communications from specified domains, supports audit logging, and requires Teams admin enabling.
Details:
Updated December 16, 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): This is now generally available.
Change Category:
XXXXXXX ... free basic plan only
Scope:
XXXXXXX ... free basic plan only
Release Phase:
General Availability, Targeted Release
Created:
2025-08-12
updated:
2025-12-18
Task Type
XXXXXXX ... free basic plan only
Docu to Check
XXXXXXX ... free basic plan only
MS How does it affect me
XXXXXXX ... free basic plan only
MS Preperations
XXXXXXX ... free basic plan only
MS Urgency
XXXXXXX ... free basic plan only
MS workload name
XXXXXXX ... free basic plan only
linked item details
XXXXXXX ... free basic plan only
Pictures
XXXXXXX ... free basic plan only
summary for non-techies**
The new integration between Microsoft Teams and Microsoft Defender for Office 365 allows security administrators to centrally manage and control which external domains can communicate with their team, enhancing security by blocking unwanted or suspicious domains and supporting audit logging for compliance.
Direct effects for Operations**
Blocked Communications
If the change is implemented without preparation, users may experience unexpected blocks on communications from 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 confusion and frustration due to sudden inability to communicate with external partners or clients, impacting productivity and user satisfaction.
- 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 Issues
Without proper preparation, the audit logs may not be correctly configured, leading to potential compliance issues and difficulties in tracking domain block actions.
- 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**
XXXXXXX ... paid membership only
Opportunities**
XXXXXXX ... free basic plan only
Potentional Risks**
XXXXXXX ... paid membership only
Data Protection**
XXXXXXX ... paid membership only
IT Security**
XXXXXXX ... paid membership only
Hypothetical Work Council Statement**
XXXXXXX ... paid membership only
DPIA Draft**
XXXXXXX ... paid membership only
explanation for non-techies**
XXXXXXX ... free basic plan only
** AI generated content. This information must be reviewed before use.
a free basic plan is required to see more details. Sign up here
A cloudsocut.one plan is required to see all the changed details. If you are already a customer, choose login.
If you are new to cloudscout.one please choose a plan.
change history
| Date | Property | old | new |
| 2025-12-18 | MC Last Updated | 11/17/2025 18:26:51 | 2025-12-16T21:16:24Z |
| 2025-12-18 | MC Messages | 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). | Updated December 16, 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): This is now generally available. |
| 2025-12-18 | MC End Time | 03/02/2026 08:00:00 | 2026-01-30T08:00:00Z |
| 2025-12-18 | MC 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. | 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, available with Defender Plan 1 or 2, blocks communications from specified domains, supports audit logging, and requires Teams admin enabling. |
| 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
