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.
PowerDNS Backend Development Kit allows a developer to code backends which can be loaded at runtime by PowerDNS, a nameserver that reads data from different backends. The stock distribution comes with MySQL and PostgreSQL and other backends. It is also possible to do failover, loadbalancing, and geodirection from a backend.
Poslib is a library which provides easy access to the Domain Name System. The client part can be used to create DNS client applications, while the server part lets you easily create a multi-threaded DNS server program, portable to many operating systems including Linux, FreeBSD, and Windows.
FollowMeIP is a small client that allows you to retrieve the IP address of your machine over the Web. It works by periodically sending your IP address to the FollowMeIP server, from where you can retrieve it using a password. It is ideal for people that are running servers on dynamic IP connections, or are away from home and want to access their machines.
With a small codebase, the PowerDNS Recursor is an advanced resolver currently serving the DNS resolving needs of over 80 million Internet connections. Besides high performance (using kqueue or epoll, over 100 thousand qps on commodity hardware), it provides advanced anti-spoofing measures. In addition, the program caches server performance and timeouts, making it both network and user friendly. It also has built-in hooks for making graphs with rrdtool, providing insight into nameserver performance.
The Zero Calorie DNS is a domain name server for which the binary weighs in at 26K, that has no dependencies other than the minimal FreeBSD 6.0 installation. The server responds to "name server" (NS), "start of authority" (SOA), "address record" (A), "reverse address" (PTR), and "mail exchanger" (MX) requests. The server is fairly fast because the feature set has been trimmed down to the bare minimum. A few things are hard-coded so that a two minute setup is easy to accomplish. The hard-coding means that it may not be for everyone, however.