# NLnetLabs/unbound

Unbound is a validating, recursive, and caching DNS resolver.

Repository: https://github.com/NLnetLabs/unbound
Canonical: https://ross.abutalabs.com/products/unbound
Homepage: https://nlnetlabs.nl/unbound
Language: C
License: BSD-3-Clause
License Family: permissive
Topics: dns, dnssec, resolver, dns-privacy, recursor
Last push: 2026-08-26T14:50:40+00:00

## Health v2 (maintenance only)
Score: 94/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 99, release rhythm 84, longevity 100
- inputs: {"age_days": 3368, "days_push": 7, "days_rel": 29, "gap_med": 49.0, "n_releases_24m": 11}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 4818, forks 448 (observed 2026-08-28T04:09:00.370493+00:00)

## What it is
Unbound is a validating, recursive, and caching DNS resolver written in C, designed to be fast and lean while implementing modern open standards. It supports DNS-over-TLS and DNS-over-HTTPS for encrypted client communication, plus privacy features like query name minimisation and aggressive use of the DNSSEC-validated cache.

## Use cases
- run a local recursive DNS resolver for my machine or network
- set up a validating DNSSEC caching resolver
- encrypt DNS queries with DNS-over-TLS or DNS-over-HTTPS
- self-host a fast DNS resolver to replace my ISP's DNS
- improve DNS privacy with query name minimisation
- run a caching resolver for a home lab or router
- load a copy of the root zone with authority zones

## When to choose
- you need a recursive, caching resolver rather than an authoritative name server
- you want DNSSEC validation and encrypted DNS (DoT/DoH) out of the box
- you need a fast, lean resolver that ships in most Linux and BSD base systems
- privacy is a priority and you want standards-based features like qname minimisation

## When to avoid
- you need an authoritative name server to serve your own zones - use NSD instead
- you want a full recursive resolver library to embed in an application rather than a daemon
- you need a DNS proxy or load balancer rather than a full resolver

## Facets
- artifact type: service
- maturity: stable
- function: networking, caching, security, privacy
- domain: networking, security, privacy, self-hosted
- platform: windows, bsd, cross-platform, self-hosted
- tags: dns-resolver, dnssec, dns-over-tls, dns-over-https, recursive-resolver, caching-resolver, nlnet-labs, linux, macos

## Member repositories
- NLnetLabs/unbound (main) score 94

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:00.370493+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T18:18:33.047824+00:00, confidence not recorded.
  - readme: https://github.com/NLnetLabs/unbound (fetched 2026-08-28T04:09:00.370493+00:00, sha 0f4fa968e7cc)
  - homepage: https://nlnetlabs.nl/unbound (fetched 2026-08-29T09:01:37.656278+00:00, sha 44d222d18cfc)
  - site_page: https://nlnetlabs.nl/projects/rotonda/about (fetched 2026-08-29T09:01:37.999489+00:00, sha 4154c2f115b0)
  - site_page: https://nlnetlabs.nl/projects/nsd/about (fetched 2026-08-29T09:01:37.734954+00:00, sha 905dd67832dc)
  - site_page: https://nlnetlabs.nl/projects/cascade/about (fetched 2026-08-29T09:01:37.771983+00:00, sha 869871abb4d3)
  - site_page: https://nlnetlabs.nl/projects/domain/about (fetched 2026-08-29T09:01:37.814002+00:00, sha 8b155d84af4f)
  - site_page: https://nlnetlabs.nl/projects/ldns/about (fetched 2026-08-29T09:01:37.845994+00:00, sha b67c2eac96c3)
  - site_page: https://nlnetlabs.nl/projects/routinator/about (fetched 2026-08-29T09:01:37.898978+00:00, sha dc696b135dda)
  - site_page: https://nlnetlabs.nl/projects/krill/about (fetched 2026-08-29T09:01:37.962277+00:00, sha ff47eb952878)
  - site_page: https://nlnetlabs.nl/research/about (fetched 2026-08-29T09:01:38.077492+00:00, sha 018143de7ad3)
- Data as of 2026-08-30T08:39:29.467469+00:00.