From a readable name to the address computers actually use
A readable domain name. Memorable, meaningful, and easy to type. Does not directly tell a computer where to send a request.
A numerical IP address. This is the actual destination address used by network infrastructure to route data to the correct server.
DNS — Domain Name System — is the translation service that bridges these two representations. It receives a domain name and returns the corresponding IP address, allowing the rest of the network system to use the numerical address for actual communication. Without DNS, users would need to memorize numerical addresses rather than readable names.
A DNS resolver is a server that acts as an intermediary between devices and the authoritative name servers. Rather than each device querying the full DNS hierarchy itself, it asks the resolver, which has often already cached answers for popular domains. Resolvers are typically provided automatically by an internet service provider or carrier, though devices can be configured to use specific public resolvers.
DNS results are stored temporarily in a cache at both the resolver level and the device level. This caching reduces the number of queries that need to travel through the full resolution chain — once a name has been resolved, the result can be reused for subsequent requests to the same domain within a defined time window. The cache expiry is controlled by a TTL value attached to each DNS record, telling resolvers how long the result can be trusted before a fresh query is needed.
Finding a server establishes where information should travel, but another question concerns how that information is protected along the way. This makes protected data transmission the next useful concept to examine.