pdnsd is a Proxy DNS server for Linux and FreeBSD that is designed to cope with unreacheable nameservers (e.g. because the dial-in link is not up) in a graceful manner to prevent DNS-dependent applications like Netscape from hanging. It has a permanent disk cache (i.e. the cache contents are saved in a file on exit) and supports parallel query and a wide variety of link uptests. It also has the ability to serve some types of locally defined records.
JH2N (Java host to named conversion program) converts a hosts file to a full BIND 8 or 9 configuration. JH2N was inspired by the h2n.pl program included in the O'Reilly "DNS and BIND" book. Various options are available to enhance its operation by incuding external files. Using the simple host file syntax, very large and complex zones can be maintained.
Posadis is a domain name server for Unix and Win32 systems. It can both act as an authoritive and as a caching DNS server, and it supports standard DNS master files, zone transfers, and DNS Notify. Its modular structure allows plug-ins to define new zone types and add new functionality.
PowerDNS Authoritative Server is a high-performance authoritative nameserver with a host of backends. Besides plain BIND configuration files, PDNS reads information from MySQL, Oracle, PostgreSQL, SQLite, MongoDB, and many other databases. Backends can easily be written in any language, and a sample Perl backend is provided. PDNS powers around 30-40% of all domain names in many parts of the world, including >90% of all DNSSEC domains in Europe.
GNU Privacy Guard DNS Keyserver Client enables sending and retrieving OpenPGP keys with GnuPG to and from DNS-based keyservers. DNS-based keyservers offer several advantages over traditional HTTP-based ones, such as distributed caching, server fail-over, and geographical optimal server selection, etc.
Network Query Tool (NQT) is a one-stop solution for getting information about a domain or IP address. Instead of manually using different Unix commands or visiting numerous Web sites to investigate a host, just load Network Query Tool and enter the hostname or IP. NQT does the rest. It supports a large number of TLDs and ccTLDs.
GNU Libidn is an implementation of the Stringprep, Punycode, and IDNA specifications defined by the IETF Internationalized Domain Names (IDN) working group. It is used to prepare internationalized strings (such as domain name labels, usernames, and passwords) in order to increase the likelihood that string input and string comparison work in ways that make sense for typical users throughout the world. The library contains a generic Stringprep implementation that does Unicode 3.2 NFKC normalization, mapping and prohibition of characters, and bidirectional character handling. Profiles for iSCSI, Kerberos 5, Nameprep, SASL, and XMPP are included. Punycode and ASCII Compatible Encoding (ACE) via IDNA are supported.