What is a DNS Server (nameserver) ?

Map Of Internet 1973

About

A nameserver is a server (host) where a name service (generally DNS) program is running generally on port 53.

Server

Zone

A name server is organized in namespace information unit called ZONEs that manages DNS information for an apex domain.

Authoritative

A nameserver may be an AUTHORITY for one or more zones.

The authoritative nameserver for a zone (normally for your domain) are designed by the NS record that you can query

For instance:

nslookup -type=NS example.com 
dig -t ns DOMAIN

Configuration: zone

If you run a nameserver for a zone, the configuration file are known as zone file

These files are managed by the primary nameservers (also called master/main nameservers) and sent to the secondary nameservers (also called slave nameservers)

Type

There are four primary nameserver configuration types:

  • primary — Stores original and authoritative zone records for a certain namespace, answering questions from other nameservers and searching for answers concerning that namespace.
  • secondary — Can answer queries from other nameservers concerning namespaces for which it is considered an authority.
  • Caching-only — Offers name to IP resolution services but is not authoritative for any zones. This type of server is also known as a resolver because it executes recursive queries.
  • Forwarding — Forwards requests to a specific list of nameservers to be resolved. These servers do not resolve the query but forward it to another resolving server.

A nameserver may be one or more of these types.

For example, a nameserver can be:

  • a primary for some zones,
  • a secondary for others,
  • and only offer forwarding resolution.

Primary / Secondary

Any nameserver can be a primary and secondary nameserver for different zones at the same time, and they may also be considered authoritative for multiple zones. It all depends on the nameserver's particular configuration.

Set

You set:

  • your authoritative nameserver for your domain by updating the NS record to de
  • the DNS server used by a application by updating the resolver config

Update

Before updating your DNS server when you want to move one's domain from one registrar to another., you can check that the DNS server have a good configuration.

This is called an undelegated domain test (ie when this is not your actual public/published DNS).

For example, if you want to move your zone example.com from the nameserver “ns.example.com” to the nameserver “ns.example.org”.

Check

The https://zonemaster.fr/ of AFNIC can check the configuration of the primary and secondary DNS server:

  • actual
  • or before switching to them (option)

Public list

The database public-dns.info contains public DNS Servers that are reachable by IPv4 or IPv6. (Around 6000 Nameservers from 150 countries)

Server Software





Discover More
Map Of Internet 1973
DNS - nslookup command line

Nslookup is a DNS client program to query (ie lookup) domain name servers and get back DNS record information nslookuphost fileping Nslookup has two modes: The local DNS file is /etc/resolv.conf...
Linux - The DNS resolver (/etc/resolv.conf)

The file /etc/resolv.conf is used by the resolver. Two Domain Name System (DNS) resolver parameters (timeout and attempts) are set by default to low values when the operating system is installed. Typical...
Map Of Internet 1973
Network - Name Service

A Name service is a database name service that maps an IP name (logical address) to a destination (generally an IP address - physical address) They are installed on name server There is two: DNS...
Map Of Internet 1973
The NS record determines your DNS server

An article about the NS record (nameserver), how they are managed and how you can query them
Dns Architecture
What is DNS ? The Domain Name System

The Domain Name System (DNS) is a database of name. It's naming system (service). It holds naming information for some kind of object (not only but mainly host) DNS can be seen as the phone book of...
Map Of Internet 1973
What is a DNS A record?

An A is a type of DNS record that maps a domain name to a IP address Version 4. AAAAdomain name where: api is a relative name IN is the INTERNET class A is the A record. 164.132.99.202 is...
Map Of Internet 1973
What is a DNS CNAME (Canonical Name) ?

A CNAME (Canonical Name) is the DNS alias functionality that maps a domain name to another name. More ...
Map Of Internet 1973
What is a DNS Lookup (Request or query)?

A DNS lookup is a request to a DNS server in order to get DNS record from a DNS name a A query will get you a ipv4 address a AAAA query will get you the ipv6 address a TXT query will get your a...
Map Of Internet 1973
What is a DNS Resolver?

The resolver or recursive resolver is a method (class/interface) that: transforms: a user request (DNS query) into multiple name servers query that can provide the information. process the...
Map Of Internet 1973
What is a DNS Zone?

A dns zone: is a namespace for a domain name (in the name hierarchical tree) is composed of all labels of a domain name except the last one on the left. DNS in foo.bar.com, the zone is bar.com...



Share this page:
Follow us:
Task Runner