Hi,
Thanks for posting in Q&A platform.
Based on provided information, my understanding is there are 2 DC&DNS servers DC1 and DC2. DC1 is at site A and DC2 is at site B. For client in site A, the DNS server was configured as DC1 and DC2, DC1 is configured as the preferred DNS server and DC2 is configured as alternate DNS server. Now we want to know when the DC1 is down, whether the DC2 can work as DNS server in site A. Please correct me if my understanding is wrong.
May I know if the client in site A can ping DC2 successfully? If we need the DC2 performs as a DNS server in site A, the prerequisite is clients in site A can establish network connection with DC2.
If the client can ping DC2 when DC1 was down, then please run command nslookup + the domain name you want to resolve from client side to see if the domain name can be resolved successfully.
Best Regards,
Sunny
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