Hacker tool? Security application? Or both?

General Topics
1

Nmap (Network Mapper) is perhaps the most famous and used hacker tool that exists.

http://www.norman.com/security_center/security_center_archive/2009/71417/en

2

Hi pondus,

It is a two-sided sword, a hacker tool in the hands of those that wanna use it that way, a security testing tool for those that wanna test against vulnerabilities and weaknesses.
Similar like netcat that can be used for good and bad purposes,

polonus