Fallback DNS

Set up Fallback DNS, which acts as a fallback DNS to provide query services when the primary DNS fails or does not respond.

1. Use the -fallback parameter to designate a specific server as the fallback DNS.

   server -fallback
   

2. Equivalent configuration method:

   Use the -e -group fallback options together, which is equivalent to the above configuration.

   server -e -group fallback