Non-profit corporation dedicated to developing and maintaining production quality open source reference implementations of core Internet protocols. BIND is available here for free.

Domain Name System tools, links, and tips. [Unix]

QuickDNS and DNS Expert tools. Free trial versions, support page including DNS glossary, FAQ, mailing list. [MacOS, Windows]

A scalable DNS server. Free trial version, FAQ, technical documentation. [Windows]

A validating, recursive, and caching DNS server software product distributed in open source form under the BSD license. [Unix]

Free trial version, screenshots, client testimonials, FAQ, tutorials. Also provides a Web-based DNS lookup tool.[Windows]

DNS and DHCP server software for MS Windows, Linux, and Solaris.

PowerDNS is a non-BIND nameserver based on open-source and proprietary software.

A public-domain, open source Domain Name Server which offers both authoritative and caching features. Its main goals are security and simplicity.

A free DNS server for Unix that serves records directly from a MySQL database.