Merge pull request #4657 from MicrosoftDocs/TABL-chrisda

TABL-chrisda to Main

Author: chrisda

defender-office-365/tenant-allow-block-list-teams-domains-configure.md

@@ -15,7 +15,7 @@ ms.collection:
   - tier1
 description: Admins can learn how to block domains in Microsoft Teams using the Tenant Allow/Block List.
 ms.service: defender-office-365
-ms.date: 07/29/2025
+ms.date: 08/04/2025
 appliesto:
   - ✅ <a href="https://learn.microsoft.com/defender-office-365/eop-about" target="_blank">Default email protections for cloud mailboxes</a>
   - ✅ <a href="https://learn.microsoft.com/defender-office-365/mdo-about#defender-for-office-365-plan-1-vs-plan-2-cheat-sheet" target="_blank">Microsoft Defender for Office 365 Plan 1 and Plan 2</a>
@@ -26,6 +26,9 @@ appliesto:
 
 [!INCLUDE [MDO Trial banner](../includes/mdo-trial-banner.md)]
 
+> [!NOTE]
+> The feature described in this article is currently in Preview, isn't available in all organizations, and is subject to change.
+
 In all organizations with Microsoft Teams and cloud mailboxes, admins can create and manage block entries for domains in Microsoft Teams using the Tenant Allow/Block List. These blocked domain entries also appear 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> in the **Teams and Skype for Business users in external organizations** section:
 
 :::image type="content" source="media/tenant-allow-block-list-teams-domains.png" alt-text="Screenshot of the External access page in the Microsoft Teams admin center showing blocked domains." lightbox="media/tenant-allow-block-list-teams-domains.png":::
@@ -46,6 +49,8 @@ This article describes how security admins can manage entries for blocked domain
     - **Block only specific external domains**
   - **Allow my security team to manage blocked domains** must be :::image type="icon" source="media/scc-toggle-on.png" border="false"::: **On**.
 
+- The maximum number of domain block entries for Microsoft Teams is 4,000.
+
 - Block entries for domains in Teams never expire.
 
 - An entry should be active within 5 minutes.
@@ -65,15 +70,11 @@ This article describes how security admins can manage entries for blocked domain
 
 2. On the **Tenant Allow/Block Lists** page, select the **Teams domains** tab.
 
-3. On the **Teams domains** tab, select :::image type="icon" source="media/m365-cc-sc-create-icon.png" border="false"::: **Add**, and then select **Block**.
-
-4. In the **Block external domains in Teams** flyout that opens, configure the following settings:
-
-   - **Add domains**: Enter one domain per line, up to a maximum of 20.
+3. On the **Teams domains** tab, select :::image type="icon" source="media/m365-cc-sc-create-icon.png" border="false"::: **Block**.
 
-5. When you're finished in the **Block external domains in Teams** flyout, select **Add**.
+4. In the **Block external domains in Teams** flyout that opens, enter up to 20 domains separated by commas or line breaks, and then select **Add**.
 
-Back on the **Teams domains** tab, the entry is listed. After a few minutes, the blocked domain also appears 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>.
+Back on the **Teams domains** tab, the domain block entries are listed. After a few minutes, the blocked domains also appear 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>.
 
 ## View block entries for domains in Teams in the Tenant Allow/Block List