what are DNS servers?

DNS Servers

What are DNS servers? Domains are translated into IP addresses and vice versa using the Domain Name System or DNS. The service is used each time you type an alphanumeric address such as www.activereach.net into a browser, translating it into an IP address that is understood by the network of routers and machines on the Internet.

The DNS system is its own network and utilises servers on the Internet and locally that are known as DNS Servers, sometimes referred to as a nameserver. Every domain on the Internet must be registered and pointed to its domain name server.

DNS resolvers are name severs that do not hold authoritative information but facilitate the DNS lookup process.

The co-ordination required for the maintenance and procedures of the databases related to the namespaces is managed by an organisation called ICANN.

The DNS Network

– DNS servers communicate with each other as required
– DNS servers are organized in a hierarchy, and at the top is the root server which stores a catalogue of the Top Level domain names (TLDs) 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/organisations who are service providers on the Internet for the clients with a web browser

When the DNS server receives a DNS query, it first checks to see if it can answer the query authoritatively based on locally stored resource record information. 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 aid resolution.
The DNS servers themselves contain a number of strings of letters used as commands that dictate the different actions of that server, such as:

  • A (or Address) record – points a domain name to an IP address
  • CNAME (or Canonical) record – points a domain name to another domain name
  • MX (or Mail Exchange) record – specifies the mail server that serves a domain names email

DNS records are an essential part of how the Internet work

For further reading see:
https://en.wikipedia.org/wiki/Domain_Name_System
https://compnetworking.about.com/od/dns_domainnamesystem/f/dns_servers.htm
https://www.howstuffworks.com/dns.htm