A DNS server is used to translate a domain name into an IP address or vise versa. For example, when you type dnsknowledge.com in your web browser, an authoritative dns server translate a domain name such as dnsknowledge.com into an IP address such as 220.127.116.11. However, if you try dnsknowledgefoobarexamplefackdomain.com, you will get an error indicating non existing domain name.
Non-existent Internet Domain Names DefinitionNXDOMAIN is nothing but non-existent Internet or Intranet domain name. If domain name is unable to resolved using the DNS, a condition called the NXDOMAIN occurred. In this example, try to find out an ip address for the domain called abcquq12examfooltest.com using the nslookup or host command line option:
Host abcquq12examfooltest.com not found: 3(NXDOMAIN)Since domain name is the invalid domain, you got a NXDOMAIN response i.e an error message indicating that domain is either not registered or invalid.