02 August 2019

What is a Name Server?

A name server is a specialised online server that is used to execute queries or questions from a localised computer, inquiring about the location of a domain name’s numerous operations.

An easy way to think about name servers is to use the phone book analogy. If a person wanted to call their cable service, it would probably be easy to recall it from memory. But most of the time, they would probably want to look it up first, just to make sure. It works the same way for internet and domain names. Like a phone number, every website on the internet has a domain name.

A name server functions mainly by translating a usually human-meaningful, text-based identifier into a system-internal (often numeric) component. A common example of a name server is the server component of a DNS (Domain Name System), one of two key name spaces of the internet.

The most relevant role of DNS servers is to translate the human-memorable host names and domain names into their equivalent numeric Internet Protocol (IP) addresses. IP addresses are the second key name space of the internet used in identifying and locating computer systems and resources anywhere on the internet.

What is the domain name system?

The DNS is a service offered by Transmission Control Protocol or Internet protocol. It allows users link to other networks or computers by plain names instead of forcing them to memorise numerical IP addresses. As mentioned, the internet has two key name spaces:

  • The domain name tiers
  • The IP address system

The domain name system preserves the domain namespace and performs translation services between the two namespaces. The DNS is implemented by internet name servers. The top tier of the Domain Name System is performed by root name servers and supported by ICANN. Under the root, the resources of the internet are arranged in a tier of domains, run by specific administrators, domain name holders and registrars. A DNS name server keeps DNS records such as name server (NS), mail exchanger (MX) and address (A, AAA) records for a domain name.

Some types of name servers

There are various types of name servers based mainly on their functions. Some name servers are so named by their administrators while others are named by default.

Vanity name servers: A vanity name server is one that is so branded by the owner’s choice. Instead of the regular public name server, a user may decide to make their site appear more professional. This is can be done by placing a preferred name over the default one issued by the service provider. With a vanity name server, the public host’s name server is merely hidden behind the client’s chosen name. The IP addresses and physical servers dealing with the client’s website DNS queries are still the default designation.

Custom name servers: With a custom name server, a person can run their own to answer DNS queries for their domains. It is also essential for Virtual Private Server (VPS) and Dedicated Server clients who wish to gain root access on their servers. Root access allow users change their DNS zones on the server, and leaving it on public name servers would present a risk opportunity for server owners.

Authoritative name servers: An authoritative name server is one that provides answers to queries about names in a zone. It provides response to only requests regarding domain names that have been purposely constructed by the administrator. It is also possible to instruct name servers to give authoritative answers to requests in the same zone, while functioning as a caching name server for other zones.

An authoritative name server can either function as a primary server or a secondary server. A primary server for a specific zone is a server that keeps final versions of all records in that zone. It is recognised by an SOA (Start-of-Authority) resource record. On the other hand, a zone’s secondary server utilises an automated update system to preserve the identical version of a primary server’s database in its zone. Examples of this in application is a DNS zone transfer and file transfer protocols.

Authoritative answer

A name response shows that its answer is authoritative by setting the Authoritative Answer (AA) aspect in the response to a name request for which it is authoritative. Name servers that answer queries in zones for which they are not authoritative- for instance those of parent zones- don’t use the AA aspect.

Recursive query

If a name server is unable to respond to a request due to the absence of an entry for the hosts in its DNS cache, it may send the request recursively to other higher-ranking name servers in the tier. This is referred to as a recursive lookup or recursive query.

As a rule, authoritative name servers will suit an internet service operation. However, where only authoritative name servers are functional, every DNS query must begin with recursive queries at its DNS root zone.

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