What Is DNS?

Learn how the Domain Name System translates domain names, routes email, delegates nameservers, and uses caching.

The Domain Name System, or DNS, is the distributed directory that helps devices find internet services by name. Instead of remembering an IP address, you can type a domain and let DNS return the records needed to connect.

DNS supports much more than website addresses. It also publishes mail routes, verification records, service aliases, security policies, and the nameservers responsible for a domain.

The DNS lookup path

Your device usually asks a recursive resolver. If the answer is not cached, the resolver follows the DNS hierarchy from root servers to the top-level domain and then to the authoritative nameserver.

Important DNS record types

A and AAAA records provide IP addresses, CNAME creates aliases, MX routes email, NS delegates a zone, TXT stores policy or verification text, and SOA describes the zone.

Caching and TTL

Resolvers cache records to make browsing faster and reduce repeated queries. Each record has a TTL that suggests how long the answer may be reused.

DNS privacy and security

Encrypted DNS can protect queries between your device and resolver, while DNSSEC helps validate that signed records were not altered in transit. Neither feature makes every destination anonymous.

Frequently Asked Questions

Is DNS the same as an IP address?

No. DNS maps human-readable names to IP addresses and other records.

What happens when DNS fails?

A browser may be unable to find the server even when the server itself is online.

Why are there multiple DNS servers?

The system is distributed for scale, resilience, delegation, and caching.