High-performance authoritative DNS server

Knot DNS is a high-performance authoritative-only DNS server which supports all key features of the modern domain name system.

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Version 3.4.0

Monday, September 2, 2024

Features:

  • knotd: full DNS over TLS (DoT, RFC 7858) implementation (see 'DNS over TLS')
  • knotd: bidirectional XFR over TLS (XoT) support with opportunistic, strict, and mutual authentication profiles
  • knotd: support …
Open source

Open source

Knot DNS is open-­source. It is com­pletely free to down­load and use. The source code is avail­able un­der GPL 3+ li­cense. Our de­vel­op­ment pro­cess is trans­par­ent and driv­en by the needs of com­munity and donat­ing user­s. The tar­get plat­forms are Linux, BSD's, ma­cOS, and oth­er POSIX op­er­at­ing sys­tem­s.

Feature-packed

Feature-packed

Knot DNS provides es­sen­tial DNS fea­tures in­clud­ing in­cre­ment­al zone trans­fers (IXFR), dy­nam­ic up­dates (DDNS) and re­sponse rate lim­it­ing (RRL). More ad­vanced fea­tures in­clude auto­mat­ic DNSSEC sign­ing, dy­nam­ic A/AAAA/PTR re­cords syn­thes­is, or rap­id on-the-fly re­con­fig­ur­a­tion.

High performance

High performance

The serv­er is suit­able for any use case. With its high per­form­a­ce, un­matched DNSSEC im­ple­ment­a­tion, and oth­er fea­tures it works ex­cep­tion­ally well as a root or a TLD name serv­er. It's cap­able of non-stop op­er­a­tion. The re­spond­ing code is com­pletely lock­-­free and there­fore the serv­er achieves very high re­sponse rate.

Secure and stable

Secure and stable

In ad­di­tion to per­form­a­ce, se­cur­ity and sta­bil­ity are the oth­er key goals of the design. The code is be­ing con­stantly checked by an ex­tens­ive test­ing suite to at­tain sta­bil­ity, as­sure in­ter­op­er­ab­il­ity with oth­er DNS im­ple­ment­a­tion­s, avoid per­form­ance re­gres­sion­s, and cir­cum­vent pos­sible se­cur­ity-re­lated prob­lem­s.

Knot Resolver

The Knot Re­solv­er is a cach­ing full re­solv­er im­ple­ment­a­tion writ­ten in C and LuaJIT, in­clud­ing both a re­solv­er lib­rary and a dae­mon. Mod­u­lar ar­chi­tec­ture of the lib­rary keeps the core tiny and ef­fi­cient, and provides a state-ma­chine-­like API.