Networking & Delivery
DNS
The system that translates human-readable domain names into the IP addresses servers actually use to find each other.
DNS is the internet's address book. When someone types your domain, DNS resolves it to the IP address of the server that should answer, following a chain of records you control. A records point a name at an IPv4 address, CNAMEs alias one name to another, MX records route email. Change where your site lives by changing these records.
The catch that bites everyone is propagation and TTL. Each record has a time-to-live that tells resolvers how long to cache it, so a change can take minutes or hours to reach everyone. Set a low TTL before a migration and you cut that window down. Cloudflare offers fast, free DNS with a global anycast network, and most registrars like Namecheap and GoDaddy include basic DNS with a domain.
DNS is also a performance and reliability layer. Anycast routing sends users to the nearest nameserver, and DNS-level failover can steer traffic away from a dead server. It's quiet infrastructure until it breaks, at which point nothing resolves.
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