resolver

A resolver is a type of server that performs domain name resolution, translating human-readable domain names into IP addresses that computers use to identify each other on a network. This process is fundamental to the functioning of the internet, as it allows users to access websites and other online resources using easy-to-remember names instead of numerical IP addresses.

Resolvers are typically part of the Domain Name System (DNS), a hierarchical and decentralized naming system for computers, services, or other resources connected to the internet or a private network. When a user enters a domain name into a web browser, the resolver queries the DNS to find the corresponding IP address. This query can involve multiple steps, including checking local caches, querying root name servers, and then following the chain of authoritative name servers until the IP address is found.

Resolvers can be implemented in various ways, including recursive resolvers, which handle the entire query process on behalf of the client, and iterative resolvers, which provide information about the next step in the query process. Public DNS resolvers, such as those provided by Google and Cloudflare, are widely used by internet service providers and individuals to improve the speed and reliability of domain name resolution.

In addition to their role in DNS resolution, resolvers can also perform other functions, such as filtering malicious domains, enforcing security policies, and providing analytics on DNS queries. These additional capabilities make resolvers an essential component of modern network infrastructure, contributing to the security, performance, and reliability of the internet.