SATAN
SATAN, which stands for Security Administrator Tool for Analyzing Networks, is a set of testing and reporting tools used to deliver information about networked hosts. It has a web interface, tabulated results, and if a security hole is found it provides context-sensitive tutorials about how to proceed.
The majority of SATAN is written in Perl; requiring a web browser to display the user interface. It was first released in 1995 by authors are Dan Farmer and Wietse Venema and the logo for the software was designed by Neil Gaiman. Though somewhat antiquated, SATAN is still relevant and useful in many situations.
Note: For users offended by the name SATAN, the software contains a program called repent, which changes all occurrences of the word "SATAN" to the word "SANTA."