Unbound is a validating, recursive, and caching DNS server software product from NLnet Labs, VeriSign Inc., Nominet, and Kirei. It is distributed free of charge in open source form under the BSD license.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).