Microsoft Defender for Office 365
Email and collaborationTenant Allow Block List Teams Domains Configure
In brief
The article updates permission and portal navigation formatting, adds the Teams senders table’s Value column, and renames the closing section to Related content.
What Defender admins need to know
Administrators can follow the revised formatting when managing Teams sender entries; no action is required.
Summaries are generated from the documentation change itself.
Documentation change
View on Microsoft LearnThe comparison below shows only the changed extract. Use the full-page view for complete context.
Before adding a block entry, check the Microsoft Teams external domain anomalies report to identify suspicious external domains that might need to be blocked.
After you add the block entry for the domain or sender address in Teams, all new Teams communication from that organization is blocked. Block communication includes new Teams meetings, chats, channels, and calls.
On the Organization settings tab of the External access page in the Microsoft Teams admin center at https://admin.teams.microsoft.com/company-wide-settings/external-communications, the following settings are required to create and manage block entries for domains and senders in Teams using the Tenant Allow/Block List:
- Teams and Skype for Business users in external organizations must be Allow all external domains or Block only specific external domains.
A blocked domain or sender entry in Teams should be active within 24 hours.
You need to be assigned permissions before you can do the procedures in this article. You have the following options:
- Microsoft Entra permissions: Membership in these roles gives users the required permissions
andand_ permissions for other features in Microsoft 365:- Add, modify, and delete entries: Membership in the Global Administrator*, Teams Administrator, Security Administrator, or Security Operator roles.
- Read-only access to entries: Global Reader
,or Security Reader roles.
- Microsoft Entra permissions: Membership in these roles gives users the required permissions
View block entries for domains and addresses in Teams in the Tenant Allow/Block List
In the Microsoft Defender portal at https://security.microsoft.com, go to Email & collaboration > Policies & rules > Threat policies > Tenant Allow/Block Lists in the Rules section. Or, to go directly to the Tenant Allow/Block Lists page, use https://security.microsoft.com/tenantAllowBlockList.
Select the Teams senders tab.
On the Teams senders tab, you can sort the entries by clicking on an available column header. The following columns are available:
- Value: The domain or email address.
Use the :::image type="icon" source="media/defender-portal-icon-search.png" border="false"::: Search box and a corresponding value to find specific entries.
Remove block entries for domains and addresses in Teams in the Tenant Allow/Block List
Use the following steps to remove blocked domain or sender address entries from the Teams senders list.
In the Microsoft Defender portal at https://security.microsoft.com, go to Email & collaboration > Policies & rules > Threat policies > Rules section > Tenant Allow/Block Lists.
Or, toYou can also go directly to the Tenant Allow/Block Listspage, usepage via https://security.microsoft.com/tenantAllowBlockList.On the Tenant Allow/Block Lists page, select the Teams senders tab.
Back on the Teams senders tab, the entry is no longer listed. After a few minutes, the blocked domain and addresses disappears from the Organization settings tab of the External access page in the Microsoft Teams admin center at https://admin.teams.microsoft.com/company-wide-settings/external-communications.
Related articlescontent
For guidance on Teams external access, Teams submissions, and other Tenant Allow/Block List entry types, see the following articles:
@@ -46,7 +46,7 @@ Review the following requirements and considerations before you create or manage - Before adding a block entry, check the [Microsoft Teams external domain anomalies report](/microsoftteams/teams-analytics-and-reports/external-domain-anomalies-report) to identify suspicious external domains that might need to be blocked. -- After you add the block entry for the domain or sender address in Teams, all new Teams communication from that organization is blocked. Block communication includes new Teams meetings, chats, channels, and calls. +- After you add the block entry for the domain or sender address in Teams, all new Teams communication from that organization is blocked. Block communication includes new Teams meetings, chats, channels, and calls. - On the **Organization settings** tab of the **External access** page in the Microsoft Teams admin center at <https://admin.teams.microsoft.com/company-wide-settings/external-communications>, the following settings are required to create and manage block entries for domains and senders in Teams using the Tenant Allow/Block List: - **Teams and Skype for Business users in external organizations** must be **Allow all external domains** or **Block only specific external domains**.@@ -62,9 +62,9 @@ Review the following requirements and considerations before you create or manage - A blocked domain or sender entry in Teams should be active within 24 hours. - You need to be assigned permissions before you can do the procedures in this article. You have the following options:- - [Microsoft Entra permissions](/entra/identity/role-based-access-control/manage-roles-portal): Membership in these roles gives users the required permissions _and_ permissions for other features in Microsoft 365:- - _Add, modify, and delete entries_: Membership in the **Global Administrator**<sup>\*</sup>, **Teams Administrator**, **Security Administrator**, or **Security Operator** roles.- - _Read-only access to entries_: **Global Reader**, or **Security Reader** roles.+ - [Microsoft Entra permissions](/entra/identity/role-based-access-control/manage-roles-portal): Membership in these roles gives users the required permissions and_ permissions for other features in Microsoft 365:+ - *_Add, modify, and delete entries_*: Membership in the **Global Administrator**<sup>\*</sup>, **Teams Administrator**, **Security Administrator**, or **Security Operator** roles.+ - *_Read-only access to entries_*: **Global Reader** or **Security Reader** roles. > [!IMPORTANT] > <sup>\*</sup> Microsoft strongly advocates for the principle of least privilege. Assigning accounts only the minimum permissions necessary to perform their tasks helps reduce security risks and strengthens your organization's overall protection. Global Administrator is a highly privileged role that you should limit to emergency scenarios or when you can't use a different role.@@ -86,21 +86,20 @@ Review the following requirements and considerations before you create or manage ## View block entries for domains and addresses in Teams in the Tenant Allow/Block List -In the Microsoft Defender portal at <https://security.microsoft.com>, go to **Email & collaboration** \> **Policies & rules** \> **Threat policies** \> **Tenant Allow/Block Lists** in the **Rules** section. Or, to go directly to the **Tenant Allow/Block Lists** page, use <https://security.microsoft.com/tenantAllowBlockList>.+1. In the Microsoft Defender portal at <https://security.microsoft.com>, go to **Email & collaboration** \> **Policies & rules** \> **Threat policies** \> **Tenant Allow/Block Lists** in the **Rules** section. Or, to go directly to the **Tenant Allow/Block Lists** page, use <https://security.microsoft.com/tenantAllowBlockList>. -Select the **Teams senders** tab.+1. Select the **Teams senders** tab. -On the **Teams senders** tab, you can sort the entries by clicking on an available column header. The following columns are available:+1. On the **Teams senders** tab, you can sort the entries by clicking on an available column header. The following columns are available:+ - **Value**: The domain or email address. -- **Value**: The domain or email address.--Use the :::image type="icon" source="media/defender-portal-icon-search.png" border="false"::: **Search** box and a corresponding value to find specific entries.+1. Use the :::image type="icon" source="media/defender-portal-icon-search.png" border="false"::: **Search** box and a corresponding value to find specific entries. ### Remove block entries for domains and addresses in Teams in the Tenant Allow/Block List Use the following steps to remove blocked domain or sender address entries from the Teams senders list. -1. In the Microsoft Defender portal at <https://security.microsoft.com>, go to **Email & collaboration** \> **Policies & rules** \> **Threat policies** \> **Rules** section \> **Tenant Allow/Block Lists**. Or, to go directly to the **Tenant Allow/Block Lists** page, use <https://security.microsoft.com/tenantAllowBlockList>.+1. In the Microsoft Defender portal at <https://security.microsoft.com>, go to **Email & collaboration** \> **Policies & rules** \> **Threat policies** \> **Rules** section \> **Tenant Allow/Block Lists**. You can also go directly to the **Tenant Allow/Block Lists** page via <https://security.microsoft.com/tenantAllowBlockList>. 2. On the **Tenant Allow/Block Lists** page, select the **Teams senders** tab. @@ -116,9 +115,7 @@ Use the following steps to remove blocked domain or sender address entries from Back on the **Teams senders** tab, the entry is no longer listed. After a few minutes, the blocked domain and addresses disappears from the **Organization settings** tab of the **External access** page in the Microsoft Teams admin center at <https://admin.teams.microsoft.com/company-wide-settings/external-communications>. -## Related articles--For guidance on Teams external access, Teams submissions, and other Tenant Allow/Block List entry types, see the following articles:+## Related content - [Managing external access in Teams admin center](/microsoftteams/trusted-organizations-external-meetings-chat?tabs=organization-settings#specify-trusted-microsoft-365-organizations) - [Report false positives and false negatives in Teams](submissions-teams.md)