Domains & DNS Basics

On this page you’ll learn key concepts about:

  • Domain registration
  • Domain Name System (DNS)

Domain registration

You can learn more about key concepts involving domain registration by learning answers to the following questions:

  • What is a domain name?
  • What is a domain registrar?
  • What is a domain registry?
  • What is a top-level domain (TLD)

What is a Domain name?

A domain name is the name, such as, that a user enters in a web browser to access a website or a web application. To make your website or web application available on the internet, you start by registering a domain name. For more information, see How domain registration works.

What is a Domain registrar?

A domain registrar is a company that processes domain registrations for top-level domains (TLDs). For example, Rocket Domains is a domain registrar for .com, .net, .org and other top level domains.

What is a Domain Registry?

A domain registry is an organization that manages the registration of domain names within the domains for which it is responsible, controls the policies of domain name allocation, and technically operates its domain. For example, VeriSign is the registry that has the right to sell .com domains. A domain registry defines the rules for registering a domain, such as residency or industry requirements. A domain registry also maintains the authoritative database for all of its domain names. The registry’s database contains information such as ownership information, contact information and the name servers for each domain.

What is a top-level domain (TLD)?

A TLD is the suffix of a domain name, such as .com, .org, or .site etc. There are two types of top-level domains: Generic TLDs and Geographic TLDs

What is a Generic top-level domains?

The Generic TLDs give users an idea of what they’ll find on the website. For example, domain names that have a TLD of .lawyer often are associated with websites for lawyers and law firms. With a few exceptions, however, you can use any generic TLD you want for your website, so a soccer club could use the .com, .soccer, or for their domain name.

What is a Geographic top-level domains?

The Geographic top-level domains are TLDs that are associated with geographic locations such as countries or cities. Some registries for geographic TLDs have residency requirements, while others, such as .co (Columbia Country), promote their use as a generic TLD.

Domain Name System (DNS) Key Concepts

You can learn key concepts involving Domain Name System by learning answers to the following questions:

  • What is an alias record
  • authoritative name server
  • DNS query
  • DNS resolver
  • Domain Name System (DNS)
  • hosted zone
  • IP address
  • name servers
  • private DNS
  • recursive name server
  • record (DNS record)
  • subdomain
  • time to live (TTL)

alias record

A type of record that you can create to route traffic.

authoritative name server

A name server that has definitive information about one part of the Domain Name System (DNS) and that responds to requests from a DNS resolver by returning the applicable information. For example, an authoritative name server for the .com top-level domain (TLD) knows the names of the name servers for every registered .com domain. When a .com authoritative name server receives a request from a DNS resolver for, it responds with the names of the name servers for the DNS service for the domain.

The name servers know how you want to route traffic for your domain and subdomains based on the records that you created in the hosted zone for the domain.

For example, if a name server receives a request for, it finds that record and returns the IP address, such as, that is specified in the record.

DNS query

Usually a request that is submitted by a device, such as a computer or a smart phone, to the Domain Name System (DNS) for a resource that is associated with a domain name. The most common example of a DNS query is when a user opens a browser and types the domain name in the address bar. The response to a DNS query typically is the IP address that is associated with a resource such as a web server. The device that initiated the request uses the IP address to communicate with the resource. For example, a browser can use the IP address to get a web page from a web server.

DNS resolver

A DNS server, often managed by an internet service provider (ISP), that acts as an intermediary between user requests and DNS name servers. When you open a browser and enter a domain name in the address bar, your query goes first to a DNS resolver. The resolver communicates with DNS name servers to get the IP address for the corresponding resource, such as a web server. A DNS resolver is also known as a recursive name server because it sends requests to a sequence of authoritative DNS name servers until it gets the response (typically an IP address) that it returns to a user’s device, for example, a web browser on a laptop computer.Domain Name System (DNS)

A worldwide network of servers that help computers, smart phones, tablets, and other IP-enabled devices to communicate with one another. The Domain Name System translates easily understood names such as into the numbers, known as IP addresses, that allow computers to find each other on the internet.

hosted zone

A container for records, which include information about how you want to route traffic for a domain (such as and all of its subdomains (such as,, and A hosted zone has the same name as the corresponding domain.

For example, the hosted zone for might include a record that has information about routing traffic for to a web server that has the IP address, and a record that has information about routing email for to two email servers, and Each email server also requires its own record.

IP address

A number that is assigned to a device on the internet—such as a laptop, a smart phone, or a web server—that allows the device to communicate with other devices on the internet. IP addresses are in one of the following formats:

  • Internet Protocol version 4 (IPv4) format, such as
  • Internet Protocol version 6 (IPv6) format, such as 2001:0db8:85a2:0000:0000:abcd:0001:2353

You can create records that have a type of A, for IPv4 addresses, or a type of AAAA, for IPv6 addresses.

Name servers

Servers in the Domain Name System (DNS) that help to translate domain names into the IP addresses that computers use to communicate with one another. Name servers are either recursive name servers (also known as DNS resolver) or authoritative name servers.

For an overview of how DNS routes traffic to your resources, see How DNS routes traffic for your domain.

Private DNS

A local version of the Domain Name System (DNS) that lets you route traffic for a domain and its subdomains.

DNS record

An object in a hosted zone that you use to define how you want to route traffic for the domain or a subdomain. For example, you might create records for and that route traffic to a web server that has an IP address of


A domain name that has one or more labels prepended to the registered domain name. For example, if you register the domain name, then is a subdomain. If you create the hosted zone for the domain, then is a subdomain.

To route traffic for a subdomain, create a record that has the name that you want, such as, and specify the applicable values, such as the IP address of a web server.

time to live (TTL)

The amount of time, in seconds, that you want a DNS resolver to cache (store) the values for a record before submitting another request to DNS Server to get the current values for that record. If the DNS resolver receives another request for the same domain before the TTL expires, the resolver returns the cached value.

A longer TTL reduces your DNS queries. A shorter TTL reduces the amount of time that DNS resolvers route traffic to older resources after you change the values in a record, for example, by changing the IP address for the web server for