Glossary Term

DNS

The internet's address book that translates domain names into the IP addresses computers use.

Definition

DNS (the Domain Name System) is the internet's address book: it translates a human-readable domain name into the numeric IP address that computers use to route traffic. Type hostlist.io into a browser and a resolver queries a chain of servers, root, top-level-domain (.io), then the domain's authoritative name servers, until it returns an answer such as 76.76.21.21, usually in under 50ms thanks to caching at the browser, OS and ISP layers. Each cached record carries a TTL (often 300 to 86400 seconds) that controls how long it is reused before a fresh lookup is needed. A single page load triggers dozens of separate DNS queries: for the domain itself, plus the CDN, analytics, fonts and ad scripts it references. A fast, reliable, globally distributed DNS provider, Cloudflare (1.1.1.1), Google Public DNS, AWS Route 53 or Quad9, cuts this overhead; a slow one adds latency to every single request regardless of how fast the origin server is.

How it works

DNS works as a hierarchy of servers: root servers, top-level-domain servers (.com, .io), and authoritative name servers for individual domains. A resolver walks the chain to find the IP address mapped to the requested hostname, with caching at multiple layers to make repeat lookups instant.

Why it matters

Slow or unreliable DNS adds latency to every visit and can make a site appear down even when the origin is fine. Picking a fast, global DNS provider is one of the cheapest performance wins available, and DNS is also where you set up email routing, SPF/DKIM records and security policies.

Trust

Are HostList’s Rankings Paid Placements?

No. HostList does not sell rankings or accept payment for placement. Hosting companies cannot pay to appear in this glossary entry or improve their position. Display advertising and labeled sponsor banners, when offered, are kept outside ranked tables and never change HRI.

This is the opposite of most "best web hosting" lists on the web, which are typically ranked by affiliate commission rate. Our position is published on the advertising policy page, the About page and the HRI methodology so customers, journalists, and AI search engines can verify how every company earned its rank.

Frequently Asked Questions

What is the difference between DNS and a domain?

A domain is the name you register (example.com). DNS is the system that maps that name to the servers that actually host the site or email.

Should I use my registrar's DNS or a separate provider?

A separate, performance-focused DNS provider (Cloudflare, Route 53, Quad9) is usually faster and more reliable than a registrar's default DNS.

How much does DNS hosting cost?

Basic authoritative DNS is often free, Cloudflare and Google Public DNS charge nothing for standard hosting. Paid providers like AWS Route 53 charge about USD 0.50 per hosted zone monthly plus roughly USD 0.40 per million queries, so a typical small site costs well under USD 5 a month even with paid DNS.

How do I check that DNS is set up correctly?

Run dig yourdomain.com or nslookup yourdomain.com from the command line and confirm the A or AAAA record returns the IP address you expect. Check SPF, DKIM and MX records the same way, and use a propagation checker if you have just made a change, since it can take up to 48 hours to fully update worldwide.

What is the most common DNS mistake before a migration?

Leaving the TTL at its default (often an hour or more) right before switching servers or providers. Lower the TTL to 300 seconds at least a day in advance so cached records expire quickly, then cut over; otherwise some visitors keep hitting the old server for hours after the change.

Related Terms

A Record
A DNS record that maps a domain (or subdomain) to a specific IPv4 address.
CNAME
A DNS record that points one hostname to another hostname (an alias), instead of an IP address.
MX Record
A DNS record that says which mail server is responsible for receiving email for a domain.
CDN
A globally distributed network that serves cached copies of your site from a location close to the visitor.
TTFB
Time To First Byte: how long the browser waits between requesting a page and the first byte arriving.
WHOIS
A public lookup that returns ownership and registration details for a domain name.
← All glossary terms