Domain Name System (DNS) is a distributed database for TCP/IP applications that provides conversion between domain names and IP addresses.
DNS uses a hierarchical naming method to specify a meaningful name for each device on the network and uses a resolver to establish mappings between IP addresses and domain names. DNS allows users to use meaningful and easy-to-memorize domain names instead of IP addresses to identify devices.
When you check the continuity of a service, you can directly enter the domain name used to access the service instead of the IP address. Even if the IP address used to access the service has changed, you can still check continuity using the domain name, so long as the DNS server has obtained the new IP address.