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.
Username-Anarchy is a commandline tool for the generation of usernames based on the users' real names. This is useful for user account/password brute force guessing and username enumeration when usernames are based on the users’ names. By attempting a few weak passwords across a large set of user accounts, user account lockout thresholds can be avoided. Common aliases (or self-chosen usernames) from forums are also included. Features include a plugin architecture, format string-style username formats, and substitutions. When only a first initial and lastname is known (LinkedIn lists users like this), it will attempt all possible first names, common first and last names from various countries (from Familypedia and PublicProfiler), and an exhaustive list of first and lastnames from Facebook. This also includes usernames scraped from forums, ordered by popularity.
geoipgen is an IP network tool for generating geotargeted lists of IP addresses using MaxMind's GeoLite Country database. It can randomly enumerate all IP addresses or a specified number of IP addresses in a particular country or a list of countries. For example, to get all IPs for Japan in a random order, use "geoipgen jp". For a sample of 10,000 IPs from Australia and New Zealand, use "geoipgen -n 10000 au nz".
nessus-xmlrpc is a Ruby library for the Nessus XML-RPC interface. You can use it to start, stop, pause, and resume scans. It lets you watch progress and status of scans, download reports, etc. It comes with an example command line program that shows how easy it is to interact with the Nessus scanner.