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.
Aletheia is a browser-like application for sending raw HTTP requests. It is designed for debugging and finding security issues in Web applications. It is possible to apply filters on every request and response which can modify the content, for making Basic Authentication or OAuth requests, for example. Because it is possible to modify every bit of the request, it is easy to exploit Web applications. That means you can set, for example, custom Cookies or User-Agents, or send file uploads to the server. It uses the Apache HTTP core components library to send HTTP requests. This application also helps you understand how the HTTP protocol works.
YaCy is a search engine that anyone can use to index the Internet (WWW and FTP) or to create a search portal for others (Internet or intranet). The scale of YaCy is limited only by the number of users. and can index billions of web pages. In P2P mode it is fully decentralized. All users of the search engine network are equal and it is not possible for anyone to censor the content of the distributed index.
RubyDNS is a high-performance DNS server that can be easily integrated into other projects or used as a stand-alone daemon (via RExec). By default, it uses rule-based pattern matching. Results can be hard-coded, computed, fetched from a remote DNS server, or fetched from a local cache, depending on requirements. In addition, RubyDNS includes a high-performance asynchronous DNS resolver built on top of EventMachine. This module can be used by itself in client applications without using the full RubyDNS server stack.
OpenNetAdmin provides a database managed inventory of your IP network (IPAM). Each host can be tracked via a centralized AJAX-enabled Web interface that can help reduce tracking errors. It also has the ability to generate DHCP and DNS configuration for individual servers from the data stored in the database. There is a command line interface for batch scripting that can be accessed remotely or locally.
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.