Domain name, or your home address on the internet, when translated into an IP address, or a range of numbers that the machine can understand, is using a Domain Name System (DNS). The service is used each time you type an alphabetical address such as, to translate it to something that will look more like 198.102.746.4.

Since the DNS system is in fact its own network, it uses a server known as the DNS Server, or nameserver. Each domain (that is, every website on the internet) must be registered and pointed to its domain name server. The DNS network then serves the sole purpose of translating services between the domain name hierarchy and the IP addresses spaces. With many IP addresses in use, and with websites changing their IP addresses all of the time, DNS servers are processing billions of requests on the Internet at any given time.

The DNS Network

  • DNS servers communicate with each other using private network protocols
  • DNS servers are organized in a hierarchy, and at the top is the root server which stores the complete database of Internet domain names and their corresponding IP addresses
  • There are 13 root servers, named from A-M, maintained by ICANN (Internet Corporation for Assigned Names and Numbers), one residing in Japan, one in the States, one in London and so on
  • Lower level DNS servers are owned by businesses/organizations who are service providers on the Internet for the clients with a web browser

Each time a client server looks up a domain name, it queries the other server for an answer, to resolve the name. When the DNS server (resolver) receives a query, it first checks to see if it can answer the query authoritatively based on resource record information contained in a locally configured zone on the server. If the queried name does not find a matched answer at its preferred server, the query process continues, and can involve assistance from other DNS servers to help resolve the name.

The DNS servers themselves contain a number of records, that is strings of letters used as commands that dictate different actions of that server, such as:

  • Address, or the “A” record – point a domain name to an IP addressing
  • Canonical name, or the “CNAME” record – point a domain name to another domain name
  • Mail exchange, or the “MX” record – specify the mail server for a domain name

DNS records are an important aspect of how the internet works.

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