Windows domain controller VM as DNS server cannot provide DNS service to the network after power outage

Products

• VMware vSphere ESXi
• VMware vCenter Server 8.0

Issue/Introduction

Following a site power outage, Windows domain controller VMs may fail to provide DNS services even if they are powered on and the IP address is reachable from vCenter.

Symptoms include:

• vCenter is unable to access DNS services required for environment restoration.
• Windows Defender Firewall is enabled on the domain controller VM.
• Control Panel > All Control Panel Items > Windows Defender Firewall shows the Guest OS is connected to "Guest or public networks" instead of the expected "Domain networks".

 

Environment

VMware vCenter 8.x

VMware ESXi 8.x

Cause

A site power outage can disrupt the communication between vCenter and ESXi hosts, impacting Virtual Distributed Switch (VDS) configurations. When the domain controller VM boots up before the network infrastructure is fully managed/stabilized by vCenter, it may fail to identify the domain and defaults to a "Guest or public networks" location.

In this state, Windows Firewall rules often block traffic on the DNS port (53), preventing vCenter and other components from accessing DNS services.

Resolution

To restore DNS functionality and allow vCenter to manage the environment:

1. Log in to the Windows Guest OS of the affected domain controller.
2. Open Network Connections.
3. Right-click the network adapter (e.g., Ethernet0) and select Disable.
4. Wait a few seconds, then right-click the adapter again and select Enable.
5. Verify that the network location has switched to "Domain networks".
6. Once DNS service is available, proceed to restore remaining VMs through the vCenter GUI.