resolver
also: DNS resolver, name resolver
A system component that translates human-readable domain names (like example.com) into IP addresses using DNS queries. It's the mechanism that makes web addresses work by converting hostnames to the numerical addresses computers actually use.
A resolver is a client-side DNS tool that performs name resolution—converting domain names to IP addresses. When you type a URL in your browser or run ping example.com, the resolver handles the DNS lookup behind the scenes.
On Linux systems, the resolver is typically configured through /etc/resolv.conf, which specifies which DNS servers (nameservers) to query. The resolver sends queries to these servers and caches results to speed up subsequent lookups.
Modern systems also use systemd-resolved or nscd (Name Service Cache Daemon) for enhanced caching and management. You can test your resolver with tools like nslookup example.com or dig example.com to see which nameserver is being used and what IP address is returned.