The Domain Name System (DNS) translates human-readable domain names into the IP addresses computers use to communicate. When you type a website address into a browser, a DNS lookup is normally required before a connection can be made.
A recursive DNS resolver handles this lookup on behalf of a client. If the answer is not already in its cache, the resolver follows the DNS hierarchy, querying root servers, top-level domain servers and ultimately the authoritative server responsible for the requested domain. It then returns the answer to the client and usually caches the result so future requests can be answered more quickly.
This differs from an authoritative DNS server. An authoritative server stores and serves DNS records for domains under its control. It does not normally search elsewhere for an answer. A recursive resolver, by contrast, is concerned with finding answers, validating them where appropriate, and returning them to users or applications.
The terminology can be slightly confusing because a recursive resolver is itself a type of DNS server. The important distinction is the role it performs. Recursive resolvers may also provide caching, DNSSEC validation, access controls, filtering, encrypted DNS support and policy features. Running your own resolver can provide greater control over DNS behaviour, privacy, security and performance.
Here’s our verdict on the finest recursive DNS resolvers captured in a legendary LinuxLinks-style ratings chart. Only free and open source software is eligible for inclusion.
Click the links to learn more about each tool.
| DNS Servers | |
|---|---|
| BIND | Flexible, full-featured DNS system |
| PowerDNS | Authoritative server, the Recursor, and Dnsdist |
| Knot Resolver | Scalable caching resolver with DNSSEC validation and flexible policy |
| Technitium | Self host a DNS server for privacy and security |
| Unbound | Validating, recursive, caching DNS resolver |
| SDNS | Fast recursive DNS resolver with built-in DNSSEC validation |
| Hickory | Rust-based DNS client, server and resolver |
| rDNS | Compact DNS server supporting recursive and authoritative operation |
| MaraDNS | Small DNS server |
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