Hackers like to discover, understand and share the secrets they expose. They like to laugh at the dumb things they find. They’re not necessarily in it for the money, more so for the glory of mastering the arcane technicalities of computing. Hackers form a community where the most “l33t” (pron. “leet”, short for “elite”) hackers gain the most respect.
But these days any “noob” (short for “newbie”) can download software tools from the internet that take the hard work out of hacking. These tools are often written by malicious hackers, professional security testers or enthusiasts to increase productivity. However, one might think of these as unhealthy professions, like comfort women. The point of view is what’s most important.
Port scanning is a process of finding all of the computers on a network, and finding out all about them. It is a precursor to a malicious hacker (or a penetration tester) launching an attack. It’s like a lion finding the slowest gazelle in the herd. Find all of the gazelles, test their weaknesses, pick the slowest.
Fydor wrote the NMAP port scanner in 1997 and has been adding functionality ever since. NMAP finds responding computers (by scanning IP addresses), finds services running on them (by scanning ports) and identifies operating systems.
It runs from the command line. Something as simple as “nmap 192.168.1.0/24” will scan your local network and find your router, PC, game console and phone (if they are connected) and tell you all about them.
There is a GUI version called Zenmap if you don’t like typing. It also has visualisation tools which display the network.
NMAP is an essential tool for network maintenance, and I use it all the time when setting up computers, to diagnose networking problems and to find out just what my DHCP server has been doing.
Images from www.behindthefirewalls.com and www.snapfiles.com