Configuring Microsoft 365 Information Barriers to Block Cross‑Team Communication

Problem: Users in separate departments can still chat and share files, creating compliance risk

Many organizations need to prevent certain groups—such as research and sales teams—from communicating in Teams, sharing files in SharePoint/OneDrive, or exchanging email when using the new Outlook experience. Without a barrier, inadvertent data leakage can occur, especially when handling regulated information.

Thesis: A properly scoped Information Barriers (IB) policy, built on Azure AD groups, enforces these communication blocks across Teams, SharePoint, OneDrive, and Outlook while remaining transparent to end users.

1. Prerequisites and planning

• Azure AD groups that accurately represent the user populations you want to separate. Overlapping group membership can cause unintended blocks or allowances.
• Administrator role: Compliance Administrator or Global Administrator (required to run the IB PowerShell cmdlets).
• Ensure the tenant is using the new Outlook experience; IB does not apply to classic Outlook.

2. Worked example: creating a block policy

Suppose you have two Azure AD security groups: ResearchTeam and SalesTeam. You want to prevent any chat, call, meeting, or file sharing between members of these groups.

# Connect to the compliance center (run once per session)
Connect-IPPSSession

# Create the Information Barriers policy
New-InformationBarriersPolicy -Name "ResearchSalesBlock" \
    -AssociatedGroup "ResearchTeam" \
    -Segments @(@{Name="ResearchSegment"; Groups="ResearchTeam"},
                @{Name="SalesSegment"; Groups="SalesTeam"}) \
    -PolicyMode "Audit"

Explanation:

• -Name assigns a friendly identifier.
• -AssociatedGroup is optional but helpful for reporting.
• -Segments defines each side of the barrier; each segment lists the groups that belong to that side.
• -PolicyMode starts in "Audit" so you can verify impact before enforcing.

The cmdlet returns a policy object containing the policy identity (GUID) and current mode. No specific output is guaranteed; inspect the returned object to confirm the policy was created.

3. Verifying the barrier

After creation, IB evaluation occurs within a few minutes to up to an hour due to Azure AD replication latency. To check:

# Replace  with a user’s user principal name from one of the groups
Get-InformationBarriersUserStatus -UserPrincipalName ""

The result shows the effective mode for that user (Audit, Enforce, or NotApplicable). You can also attempt a Teams chat between a member of ResearchTeam and a member of SalesTeam; the blocked user should see the generic message “You can't communicate with this person”. In Outlook, sending mail to the blocked address generates a nondelivery report without revealing the barrier.

Audit events are logged in the compliance center under **Information Barriers** activity. Search for InformationBarriersPolicyApplied to confirm when the policy was evaluated for a given user or interaction.

4. Trade‑offs and limitations

• Scope: IB only protects Teams, SharePoint, OneDrive, and Outlook (new experience). Legacy SharePoint on‑premises, Yammer, and third‑party apps that do not respect Microsoft 365 compliance boundaries are not covered.
• Group design: Overlapping or nested groups can produce contradictory evaluations; pilot testing with a small subset of users is essential.
• No encryption: IB prevents communication but does not encrypt data or stop data exfiltration via other channels (e.g., forwarding email to personal accounts, downloading files to a local device).
• Exemptions: Users assigned to the InformationBarriersExempt role or administrators with privileged bypass can still communicate across the barrier.

5. Actionable closing and rollback

Once you have validated the policy in Audit mode, switch to enforcement:

Set-InformationBarriersPolicy -Identity "ResearchSalesBlock" -PolicyMode "Enforce"

Monitor user feedback and audit logs for any false positives. If you need to remove the barrier entirely:

Remove-InformationBarriersPolicy -Identity "ResearchSalesBlock"

Removing the policy deletes the configuration; existing chat history and shared files remain unaffected, but new communications will no longer be blocked.

By basing the barrier on well‑defined Azure AD groups, starting in Audit mode, and verifying with Get-InformationBarriersUserStatus, you can confidently enforce communication boundaries that meet compliance requirements without disrupting legitimate collaboration.