Delete or Replace registry HKLM\SOFTWARE\Microsoft\SIH\dns\data

Question

On Windows Server, is there a way to configure Windows Server 2019 and 2022 severs to stop using Cloudflare DNS (162.159.36.2) for resolving DNS queries for fe3cr.delivery.mp.microsoft.com, specifically for Windows Update.

Reg Path:

HKLM\SOFTWARE\Microsoft\SIH\dns\data

1. Are there any issues when deleting this registry key and whether it will impact the functionality of Windows Update or other Microsoft services.
2. Can we replace the DNS (162.159.36.2) with a private DNS IP in the value HKLM\SOFTWARE\Microsoft\SIH\dns\data

Answer 1

AFAIK, the registry key HKLM\SOFTWARE\Microsoft\SIH\dns\data is related to the Server Initiated Healing (SIH) component, which is part of Windows Update and self-healing mechanisms in Windows. Modifying or deleting this key could indeed have implications on Windows Update functionality and other related services.

1. Impact of Deleting the Registry Key Deleting the dns\data key removes the ability of the SIH component to override default DNS settings for resolving specific domains like fe3cr.delivery.mp.microsoft.com. This could result in Windows Update failing to reach Microsoft servers if the system relies on the overridden DNS settings. Some updates or self-healing mechanisms may fail to function if this DNS override is required for specific Microsoft services.

However, if your internal DNS can resolve fe3cr.delivery.mp.microsoft.com correctly without using the Cloudflare DNS (162.159.36.2), then the deletion may not have a noticeable impact.

2. Replacing Cloudflare DNS with a Private DNS Replacing the DNS entry with a private DNS IP in HKLM\SOFTWARE\Microsoft\SIH\dns\data can work, provided:

• The private DNS resolves fe3cr.delivery.mp.microsoft.com accurately to Microsoft's update servers.
• The private DNS has no restrictions or blocks on outbound queries related to Microsoft's content delivery network (CDN).

Test DNS resolution of fe3cr.delivery.mp.microsoft.com through your private DNS before making changes.

In any case, you would obviously want to test this configuration before you deploy it into your production environment. In addition, note that this registry key might be updated or restored during cumulative updates or system repairs, so you might want to periodically review and validate the settings.

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hth

Marcin