What Is a Domain, and Why Do You Need One? Nameservers and DNS Records

When you build a website or run a service, the first word you run into is domain. An address like schoolofweb.net is a domain — but if someone asks “what exactly is a domain, and why do I have to pay money for one?”, it’s surprisingly hard to answer.

In this post I’ll lay out, at a concept level and without code, what a domain is and why you need one, and what the nameservers and DNS records that make that name actually work are. How to set those records up in practice is covered in a separate post.

A domain is an internet address people can remember #

Every computer connected to the internet has a numeric address called an IP address, in a form like 93.184.216.34. Computers find each other just fine with these numbers, but it’s hard for a person to memorize a clump of digits every time.

So we agreed to use easy-to-remember names instead, and that’s the domain. When you type schoolofweb.net, somewhere on the internet that name is turned into the actual server’s IP address and the connection is made. A domain is, in the end, a name tag for people, and the real address is the number hidden behind it.

Why do you need a domain when there’s already an IP address? #

A name isn’t useful only because it’s easy to remember. There are a few more reasons a domain is essential.

• It keeps your address even when the server changes. Move a site to a different server or a different company’s hosting and the IP address changes. But you leave the domain name as is and just change the number it points to, so visitors never notice the address moved.
• It becomes a brand. A numeric address doesn’t stick in memory, but a name does. A domain is a unique name that works wherever you write it — on a business card, an ad, an email.
• It’s the basis for email. A work address in the form name@yourcompany.com is only possible when you have a domain.

In short, a domain is a signboard that doesn’t change, and the IP address behind it is the actual location you can swap out at any time.

You don’t buy and own a domain — you rent it #

A domain isn’t an object that becomes yours forever once you buy it; it’s closer to renting the right to use it for a set period. Through a registrar you usually pay a yearly fee, and you have to renew before the term ends to keep using it. Miss the renewal and you hand the name back, and the address and email you built on it can all stop at once. If you’re curious about how domains are bought and sold, I covered it in detail in How Domain Names Are Bought and Sold.

The directory that turns names into numbers: the nameserver #

Registering a domain doesn’t open your site right away. First you have to decide “when someone asks about this name, who will answer?” The place responsible for that answer is the nameserver.

When you register a domain, you designate “this nameserver handles the lookups for this domain.” After that, when someone types the domain into a browser, the internet asks the nameserver in charge of that domain “what’s the real address for this name?”, and the nameserver returns the answer it has on file. This whole lookup system that turns names into numbers is called DNS. How DNS finds the answer step by step is laid out in Why a Site Suddenly Goes Down.

There’s one point that’s easy to confuse here: the place you bought the domain (the registrar) and the place that actually handles its lookups (the nameserver operator) aren’t necessarily the same. You can buy the domain from company A and leave the lookups to company B’s nameservers. Knowing this distinction helps you quickly find where to look when settings get tangled later.

DNS records are the entries you write on a domain #

A nameserver holds various pieces of guidance about a domain, entry by entry. Each of those lines is called a DNS record. Here are the main ones worth knowing even as a non-developer.

• A record: connects a name to a real IP address. It’s the most basic entry.
• CNAME record: connects a name to another name, like routing www.schoolofweb.net to schoolofweb.net.
• MX record: designates which mail server should receive email sent to this domain.
• TXT record: used when you need a short note, such as ownership verification or mail authentication.

Open a domain’s management screen and you’ll see exactly this list of records. “Connecting a site to a new server” or “moving company email to a new service” usually comes down to editing a few of these lines.

What gets easier once you know this #

• You narrow down problems faster. When a site won’t open, instead of assuming it’s always a development problem, you can look to common causes first — like domain expiration or a record misconfiguration.
• You understand migration work. You can grasp why people say “it takes time to fix and propagate the records” when moving a server or changing email.
• You can talk with the people in charge. You can understand and exchange requests like “please change the A record to the new server.”

Wrapping up #

Today we looked at what a domain is and why you need one, and at the concept of the nameservers and DNS records that make that name work. A domain is a signboard people remember, a nameserver is the directory responsible for answering for that name, and DNS records are the entries written there.

If that’s the concept, then how you actually handle A, CNAME, apex, and TTL while connecting a domain to a server or the cloud is covered hands-on in DNS Records Setup in Practice. And if you’re curious about the common cases where a site suddenly stops due to domain, DNS, or certificate trouble, Why a Site Suddenly Goes Down is worth reading too.