Help - dns
DNS stands for Domain Name Service. This is the service that provides maps
between hostnames and IP addresses. This check is performed by connecting to
the DNS server at the remote machine and asking it to provide it's own IP
address based on it's name. If the server is down, it won't be able to do this
function, and an error will be returned.
If this service is down, many problems could appear. People will report slow
networks or systems (due to timeouts while looking up addresses). People might
not be able to connect to services or systems. In general if DNS is down you
will run into multiple widespread problems.