DNS Server

A DNS server is a networked machine that answers queries about domain names, returning the IP addresses and other zone records tied to them. It is part of the distributed DNS system that lets us use readable names such as example.com instead of memorising strings of digits. Without working DNS servers, a website and its email stay unreachable even when the web server itself is running perfectly.

How a DNS server works

In practice several server types play different roles in the name-resolution chain:

• Recursive server (resolver) — accepts a user's query and asks other servers until it obtains a final answer; public resolvers such as 1.1.1.1 and 8.8.8.8 are common examples.
• Authoritative server — stores the domain's actual zone and returns binding answers about its records (pointed to by NS records).
• Caching server — remembers answers for the duration of their TTL to speed up repeated lookups and reduce network load.

The authoritative answer — for example an A record with an IPv4 address — is the source of truth; resolvers merely cache and distribute it.

DNS servers in practice

You work with DNS servers at every infrastructure change: pointing a domain at hosting, migrating to a new server, configuring email (MX, SPF, DKIM records) or deploying a CDN. Records are edited in the control panel of a DNS provider or domain registrar. Best practices include keeping at least two name servers in separate networks, lowering the TTL before a planned change, and verifying records after a migration with dig or nslookup. Many companies rely on DNS servers bundled with their hosting, which simplifies zone management from a single panel.