trusted list

Question

How do i add an external organisation to my trusted list in Microsoft Teams?

Answer 1

To add an external organization to the trusted list for Microsoft Teams meetings and chat, configure it as an allowed external domain in the Teams admin center and, optionally, in Microsoft Entra cross-tenant access.

1. Add the organization in Microsoft Entra cross-tenant access (optional but recommended)
   1. Go to the Microsoft Entra admin center and sign in as an External Identity Provider Administrator.
   2. Expand Identity > External Identities.
   3. Select Cross-tenant access settings > Organizational settings.
   4. Select Add organization.
   5. In Add organization, enter the vendor’s full domain name (or tenant ID).
   6. Select the organization from the search results and then select Add.
   7. Configure Inbound access / B2B collaboration as needed (for example, which users/groups from that org can be invited, and which apps they can access).
2. Allow the external domain for Teams external access (trusted organizations)
   1. In the Teams admin center, go to Users > External access.
   2. Under Teams and Skype for Business users in external organizations, choose the model used in the tenant:
      • To trust only specific orgs, select Allow only specific external domains.
      • To trust most orgs but exclude a few, select Block only specific external domains.
   3. If using Allow only specific external domains:
      1. Select Add external domains.
      2. In Domain, enter the external organization’s domain (for example, contoso.com).
      3. Select Done.
   4. If using Block only specific external domains, ensure the external org’s domain is not in the block list.
   5. Save the changes.

After this configuration:

• Users in the tenant and the external organization can chat and meet as external (federated) users, provided the other organization also allows the tenant’s domain and enables external access.
• In Teams, such users are treated as being from a trusted Microsoft 365 organization and will appear with the corresponding trust indicator when configured as described in the trusted organizations documentation.

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References:

• Onboard trusted vendors to collaborate in Microsoft 365
• IT Admins - Manage external meetings and chat with people and organizations using Microsoft identities
• Plan for meetings with external participants in Microsoft Teams
• Representation of users outside your organization
• Add or invite people outside your org to a chat in Microsoft Teams

Answer 2

Hi @Rhian Arnold, 

Thank you for reaching out. 

I understand that you’re looking to add an external organization to your trusted list in Microsoft Teams, which is to ensure secure and seamless collaboration.  

Here’s a step-by-step guide to help you through the process: 

Step 1: Configure Cross-Tenant Access in Microsoft Entra 

1. Sign in to the Microsoft Entra admin center as at least a Security Administrator: https://entra.microsoft.com 
2. Navigate to:  Entra ID > External Identities > Cross-tenant access settings 
3. Select Organizational settings > Add organization. 
4. On the Add organization pane, type the full domain name (or tenant ID) for the organization. 

 

5. Select the organization in the search results, and then select Add. 
6. To change the settings for this organization, select the Inherited from default link under the Inbound access or Outbound access column. 

 

Step 2: Add the External Organization in Teams Admin Center 

1. Go to the Microsoft Teams admin center: https://admin.teams.microsoft.com 
2. Navigate to:  Users > External access 
3. Under Teams and Skype for Business users in external organizations, choose:  Allow only specific external domains 

 

4. Click Add external domains 
5. In the Domain box, type the domain of the organization you want to allow (e.g., partnercompany.com) and select Done 
6. Repeat the process to add more domains if needed 

 

For more information regarding configuring cross-tenant access settings and trusted organization, please refer to these documents: 

1. IT Admins - Manage external meetings and chat with people and organizations using Microsoft identit… 
2. Cross-tenant access settings - Microsoft Entra External ID | Microsoft Learn 

I hope this information is helpful. Please follow the steps above and let me know if it works for you. If not, we can continue working together to resolve the issue.  

Thank you for your patience and understanding. If you have any questions or need additional assistance, please don’t hesitate to reach out so I can continue to support you. If you found the response useful, please consider marking it as accepted, as this may help other community members who are looking for similar guidance.  

I look forward to continuing the conversation.

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