Unavailability of one Domain Controller causes loss of Internet even though Secondary DNS was configured

[Guest /u/Feeling-Flower612]

We have a network with a domain controller that manages DNS settings for all connected client PCs. The primary DNS server is configured on the domain controller, and a secondary DNS server is also set in the Advanced TCP/IP Settings of each client PC. It was observed that, for a short duration when Domain controller was unavailable, all the client PCs were not able to access internet. Upon inspection, I found that the IP address of the secondary DNS server was present in the DNS entries on the client machines, but it did not function correctly to maintain internet connectivity when the primary DNS was down.

 

Note : We do not use DHCP for internal reasons also we used AD integrated DNS setup. And the temporary working solution was to switch the IPv4 DNS address order that is primary to secondary and secondary to primary and it worked.

 

Here are the steps I've tried so far:

 

Troubleshooting DNS Problems:

 

• 
  Tried different web browsers to rule out cache issues, but no luck there.
   
   
  
• 
  Temporarily disabled the firewall to ensure it wasn’t blocking DNS services, yet no internet service.
   
   
  
• 
  Cleared the DNS cache on the client PCs, but the issue persisted.
   
  

 

Reference Link - How to Fix “DNS Server Not Responding” Error (11 Methods)

 

Also, found recommendations to configure PCs to use public DNS servers as their primary DNS. However, I’m unsure if this would interfere with domain-related DNS queries and implement without disrupting domain functionality.

 

Is there any other recommended methods that can ensure that the client's PC can maintain internet access even if the primary domain controller is down, that is , secondary DNS should work when primary is down. Your input will be much appreciated

 

Thank you in advance

 

submitted by /u/Feeling-Flower612

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