Тhe DNS monitoring check is a part of the ClouDNS motoring service, that makes DNS queries for chosen hostname and query type on the given IP address. If the response is not equal to the expected response, the check is marked as DOWN. The DNS monitoring check validates the health of DNS servers by sending a DNS request and comparing the response IP address. For example if you choose 18.104.22.168 for IP/Host of the server you want to check, host to query - example.com, query type - A and query response - 22.214.171.124, the command that will be executed and checked is:
$ dig @126.96.36.199 example.com A
The answer will be compared with the query response IP and if they match the check will be marked as UP, otherwise it will be marked as DOWN.
*Available DNS query types - A, AAAA, NS, MX, PTR and CNAME. With DNS monitoring check, you can track multiple A, AAAA, NS, MX and PTR records for a specific hostname.
DNS server monitoring has many benefits, including improved server and application availability, quicker detection of outages and DNS-related issues, changes of your IP address configured as expected response. It is important because DNS performance is critical to your network, servers, and applications.
Each Monitoring check provides debugging option which you can use to find out where the problem comes from using Traceroute information - The traceroute command is used to determine the path between two connections. Often a connection to another device will have to go through multiple routers. The option can be found in the Monitoring check settings page on the right side of the "Uptime changes section".