Understanding the Key DNS Record Types

The Domain Name System (DNS) serves as the backbone of the internet, it orchestrate the translation of human-readable domain names (such as facebook.com) into machine-friendly IP addresses (such as 157.240.0.35 for IPv4 addresses). The DNS ensures that when you type in your web browser a domain name like google.com, your browser knows where to find the corresponding website's IP address. But behind this seamless process there are various DNS records types, each with its own role, that facilitate the Internet communication.

Let's check which are the most popular DNS record types:

1) A Record (Address Record)

The A record points a domain name to its IP address, in shorts it maps a domain name to its IPv4 address. For instance, resolving google.com via a DNS A record can return the IPv4 address 172.217.16.142. When you buy a domain name, the domain registrar assigns the NS records to the domain and then it adds the A record, that generally points to the server's IP where the website is hosted.

2) AAAA Record

As the Internet transitions to IPv6 to accommodate the growing number of devices (IPv4 addresses are limited and are near the saturation), the AAAA record gains prominence. Like the DNS A record, it maps a domain to an IP address, but for IPv6. An IPv6 address, such as 2a00:1450:4009:820::200e, provides an expanded address space and is the successor of IPv4 addresses.

3) CNAME Record (Canonical Name)

CNAME records are used as alias for another domain or subdomain. Instead of pointing to an IP address like the A records, they redirect to another domain, the canonical name. This is particularly useful for setting up subdomains or domain aliases. For instance, the CNAME DNS record of www.paypal.com points (at the moment of writing this article) to www.glb.paypal.com.

4) NS Record (Nameserver)

The NS records are the most important DNS records for a website, they designate authoritative DNS servers for a domain. Basically, they inform DNS querying systems where to locate the DNS information for a particular domain. Typically, multiple nameservers are specified to ensure redundancy and fault tolerance. An example of NS records are ns101.ovh.net and dns101.ovh.net of a website registered with OVH domain registrar. Below you can find the nameservers of google.com domain name:

5) MX Record (Mail Exchange)

MX records specify the mail servers responsible for receiving emails directed to a domain. By pointing to the appropriate mail servers, MX records ensure seamless email delivery, a domain name without MX records means the domain cannot receive emails. It is common for a domain name to have multiple MX records that allow for correct prioritization and redundancy.

DNS is a complex yet vital system that rule the functionality of the Internet. Understanding the DNS records types empowers users and system administrators to manage domain names effectively. They are important to "make your website live", to correctly point users to your website, to receive email addresses on your domain name and to manage subdomains.

Without DNS records there would be no website online or browsable.