Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
nUbuntu or Network Ubuntu is a project to take the existing Ubuntu distribution and remaster it as a Live CD and Full Install with tools needed for penetration testing servers and networks. The main idea is to keep Ubuntu's ease of use and mix it with popular penetration testing tools. Besides usage for network and server testing, nUbuntu will be made to be a desktop distribution for advanced Linux users.
Since this distribution is not updated for a long time (more than 600 days, as of june 2008), a user who wants a stable, updated, and secure system, with support for the latest hardware, can just use remastersys to easily create a customized Live CD/DVD of the latest version of ubuntu with their favorite tools and programs.