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.
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.