Unbound is a validating, recursive, and caching DNS resolver product from NLnet Labs. It is distributed free of charge in open-source form under the BSD license.
Developer(s) | NLnet Labs |
---|---|
Initial release | February 19, 2007 |
Stable release | 1.19.3[1]
/ 14 March 2024 |
Repository | Unbound by NLnetLabs on GitHub |
Written in | C |
Operating system | Unix-like, Windows |
Type | DNS server |
License | BSD license |
Website | unbound |
Originally designed by Jakob Schlyter of Kirei and Roy Arends of Nominet in 2004, funding was provided by VeriSign and ep.net to develop a prototype written in Java (David Blacka and Matt Larson, VeriSign). In 2006, the prototype was re-written for high-performance in the C programming language by NLnet Labs.[9]
Unbound is designed as a set of modular components that incorporate modern features, such as enhanced security (DNSSEC) validation, Internet Protocol Version 6 (IPv6), and a client resolver application programming interface library as an integral part of the architecture. Originally written for POSIX-compatible Unix-like operating system, it runs on FreeBSD, OpenBSD, NetBSD, macOS, and Linux, as well as Microsoft Windows.
Unbound has supplanted the Berkeley Internet Name Daemon (BIND) as the default, base-system name server in FreeBSD and OpenBSD, where it is perceived as smaller, more modern, and more secure for most applications.[10][11]