Frequently Asked Question

How does DNS actually work?

The Domain Name System turns a human-readable name like google.com into the numeric address a packet needs. When you type a name, your machine first asks a recursive resolver (typically your ISP's, or 8.8.8.8, or 1.1.1.1). If the answer isn't cached, the resolver walks the DNS tree from the top: it asks one of 13 root servers which name servers handle .com, asks those for google.com's name servers, and asks those for the actual A or AAAA record. The answer comes back, gets cached with a TTL, and you connect.

On Linux the resolver configuration lives in /etc/resolv.conf, which lists nameserver entries to use. On most modern desktops this file is generated automatically by systemd-resolved (which also caches answers and supports DNS over TLS) or by NetworkManager. /etc/hosts is consulted first and is the way to override DNS locally, that's how localhost resolves to 127.0.0.1 without any server involvement.