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How DNS Works: From Typing a URL to Loading a Page

Every time you type a website address, a background lookup called DNS quietly translates it into the numeric address computers actually use.

DNS translates names into IP addresses

Computers route traffic using numeric IP addresses, not domain names, so DNS acts as a lookup system β€” often described as the "phone book of the internet" β€” that converts a human-readable name like example.com into the correct address.

Your recursive resolver does the legwork

Usually run by your ISP or a public DNS service, this server receives your request and queries other servers on your behalf, then caches the answer so it doesn't have to repeat the same lookup for every request that follows.

Root and TLD servers point the way, layer by layer

The resolver first asks a root server which server handles a given top-level domain, like .com or .org, then asks that top-level domain (TLD) server which server is authoritative for the specific domain being looked up.

The authoritative server holds the actual answer

This server stores the domain's actual DNS records and returns the real IP address, or whatever record type was requested, back down the chain to your resolver and ultimately to your device.

Different record types answer different questions

An A record maps a name to an IPv4 address, a CNAME record points one name to another name, an MX record specifies mail servers, and a TXT record holds arbitrary text, often used for domain ownership verification.

Caching (and TTL) is why changes take time to show up

Each DNS record includes a time-to-live (TTL) value telling resolvers how long they're allowed to cache the answer before checking again, which is why updating a DNS record doesn't take effect everywhere instantly.

Why the lookup is normally invisible

A full DNS lookup can involve several servers, but caching at multiple layers β€” your browser, your operating system, and your resolver β€” means most everyday lookups are answered from a nearby cache in milliseconds. The multi-step process above mainly plays out in full the first time a name is looked up.

DNS problems are a common troubleshooting first step

Because so much depends on this lookup succeeding, "flush your DNS cache" or "try a different DNS server" are common early troubleshooting suggestions when a site won't load on one device or network but works fine elsewhere.

Frequently Asked Questions

Why do some people change their DNS server manually?

Switching from an ISP-provided resolver to a public one is sometimes done for perceived speed, privacy, or reliability reasons, or to work around certain ISP-level content filtering, though actual results vary by network and location.

Does DNS control whether a website connection is secure?

No β€” DNS only resolves a name to an address. The security of the connection itself is handled separately, through HTTPS and TLS certificates, once your device has connected to the correct server.