I used to wade through pages of security log files and reports in the hopes of keeping my network safe and my systems secure. But even after all of my analysis, I still wasn't completely sure that my systems were really protected. I was testing my systems with well-known security tools that checked for vulnerabilities, and I was spending a large part of my day reading through log files that told me a lot of details about what happened AFTER the security breaches had already occurred. I was missing important reconnaissance that would have shown me exactly what the bad guys were seeing.

I knew Nmap could help, but I wasn't sure if I was taking advantage of everything it had to offer. Although it was simple to run the default Nmap scan, I wasn't completely certain what the output really meant and the hundreds of additional scan methods and options were almost overwhelming. I found many web sites that gave me pieces of what I needed, but detailed instructions and tutorials didn't seem to be available anywhere.

To get a complete picture of Nmap's operation, I broke down every Nmap scan and every option to gain an understanding of exactly what was happening over the network. Through my research, I've made thousands of Nmap scans and sifted through millions of network packets. I've created documentation that will help you understand exactly how Nmap interacts with the devices across the network. This Professor Messer "Nmap Secrets" training course is the result of this extensive research.

Nmap is arguably the most popular security software in the world, with thousands of downloads every day. It's used in the biggest corporate networks in the world, governments use Nmap to protect their systems, and it's even seen in the Hollywood blockbuster "The Matrix Reloaded." Best of all, Nmap is free software that's well supported through an active open source community of developers.

Nmap didn't become this popular because of clever onscreen product placements. It's used so prominently because it's a powerful piece of security software that can tell you more about your systems than most people realize.

Nmap can automatically detect nearly invisible nuances in network communications to determine open ports, operating systems, and even the version numbers of your critical services - all without ever logging in or authenticating to the remote device! Nmap's scanning methods allow for reconnaissance of devices through firewalls, around gateways, or even through encrypted tunnels.