MC1189910 – M365 Change Digest

One-line summary

Chrome 142 will enforce Local Network Access restrictions, requiring admins to update policies for Microsoft eCDN peer-to-peer functionality in Teams Live Events and Town Halls.

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Details

Summary

Admins must configure the LocalNetworkAccessAllowedForUrls policy in Chrome-based browsers to allow specific Microsoft eCDN URLs, ensuring optimal Teams Live Events performance amid new Local Network Access restrictions starting with Chrome 142. Apply settings via Group Policy or registry keys; see documentation for details.

Body (from Message Center)

We're making some changes to the Microsoft eCDN configuration.

Starting with Chrome 142, browsers will enforce Local Network Access restrictions that may impact Microsoft eCDN peer-to-peer functionality.

[How this will affect your organization:]

You are receiving this message because our reporting indicates one or more users in your organization may be using this Microsoft eCDN. To maintain optimal performance for Teams Live Events and Town Halls, admins must configure the LocalNetworkAccessAllowedForUrls policy for Chrome-based browsers

[What you need to do to prepare:]

Admins will need to:

Add the following URLs to the LocalNetworkAccessAllowedForUrls policy in your environment:

[*.]ecdn.teams.microsoft.com
https://teams.microsoft.com
[*.]ecdn.teams.cloud.microsoft
https://teams.cloud.microsoft
https://engage.cloud.microsoft/

Apply these settings via Group Policy or registry keys for:

Microsoft Edge: HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Edge\
Google Chrome: HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome\

For US Government tenants, use GCC/GCC High-specific hostnames as outlined in the documentation.

Additional Notes:

This change aligns with Microsoft’s Unified Domains initiative. Ensure your network filters include both legacy and new domains.
Pair this configuration with WebRtcLocalIpsAllowedUrls for full peer-to-peer functionality.
Firefox restrictions are planned but not yet enforced.

See documentation for full guidance: Configure Local Network Access Policy for Microsoft eCDN

Raw JSON (for debugging)

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    "ai_actions": [
      "Add specified eCDN and Teams URLs to LocalNetworkAccessAllowedForUrls policy",
      "Apply settings via Group Policy or registry for Edge and Chrome",
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    ],
    "ai_master_tags": [
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    "ai_model": "gpt-4.1",
    "ai_summary": "Chrome 142 will enforce Local Network Access restrictions, requiring admins to update policies for Microsoft eCDN peer-to-peer functionality in Teams Live Events and Town Halls.",
    "ai_topics": [
      "Teams",
      "Microsoft 365 For The Web",
      "Microsoft 365 Apps",
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    ],
    "category": "planForChange",
    "details_map": {
      "Summary": "Admins must configure the LocalNetworkAccessAllowedForUrls policy in Chrome-based browsers to allow specific Microsoft eCDN URLs, ensuring optimal Teams Live Events performance amid new Local Network Access restrictions starting with Chrome 142. Apply settings via Group Policy or registry keys; see documentation for details."
    },
    "id": "MC1189910",
    "importance": 5,
    "is_major_change": false,
    "last_modified": "2025-11-26T18:38:20Z",
    "ms_products": [
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    "severity": "normal",
    "tags": [
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    "title": "Configure Local Network Access Policy for Microsoft eCDN"
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