By the mid-2000s, Nmap had established itself as the clear leader in port scanning tools—and security tools in general—whether open source or not. Although it's a constant battle to continually innovate and optimize, Nmap can only be considered as an extremely successful project.

Due to its popularity, and the fact that it's an open source project with a relatively high profile, Nmap was selected to participate in Google Summer of Code several times. Google Summer of Code is a software development internship/association project, during which students are selected and put on open source software teams to build new features into existing projects.

In May 2006—when the currently released version of Nmap was only 4.0—Nmap was selected for its second Summer of Code season. The previous year, in 2005, several improvements had been made through the students' coding for the Nmap project: the students had written a contemporary implementation of Netcat (called Ncat), upgraded...