C.2 Nameservers

The main reason why we need nameservers is that we want to use domains instead of IP addresses, although a domain is not strictly necessary for you to be able to access a website. You could use the IP address if you have your own server with a public IP, but there are many problems with this approach. For example, IP addresses are limited (in particular IPv4), not easy to memorize, and you can only host one website per IP address (without using other ports).

A nameserver is an engine that directs the DNS records of your domain. The most common DNS record is the A record, which maps a domain to an IP address, so that the hosting server can be found via its IP address when a website is accessed through a domain. We will introduce two more types of DNS records in Section C.3: CNAME and MX records.

In most cases, the default nameservers provided by your domain registrar should suffice, but there is a special technology missing in most nameservers: CNAME flattening. You only need this technology if you want to set a CNAME record for your apex domain. The only use case to my knowledge is when you host your website via Netlify, but want to use the apex domain instead of the www subdomain, e.g., you want to use example.com instead of www.example.com. To make use of this technology, you could consider Cloudflare, which provides this DNS feature for free. Basically, all you need to do is to point the nameservers of your domain to the nameservers provided by Cloudflare (of the form *.ns.cloudflare.com).