Nmap ("Network Mapper") is a free open source utility for network exploration or security auditing. It was designed to rapidly scan large networks, although it works fine against single hosts. Nmap uses raw IP packets in novel ways to determine what hosts are available on the network, what services (application name and version) those hosts are offering, what operating systems (and OS versions) they are running, what type of packet filters/firewalls are in use, and dozens of other characteristics.
Nmap runs on most types of computers and both console and graphical versions are available. Nmap is free and open source. I was interested in some DNS hack .To state it clearly, I would say that I came across this Page in between the search and Boy o boy Isnt Bob Awsome??? Read More.....Diary of a hack attack
So coming back to NMAP. Why I talking about using nmap because it is one of the acclaimed tool used by hackers ...So I used Synaptic to install nmap and nmapfe ( GUI for nmap)as I am using Ubutnu (Feisty Fawn).
fig .1 Install nmap and nmapfe using Synaptic
After installation ,Run " sudo nmapfe" in the terminal as one need Root access to use some functionalities. Once the window appears, an experiencd hacker knows what kind of attack he has to perform. Myself being a starter asked one of my Online friend to share the IP. Once i got the IP , I ran the most basic of all test , the SYN Stealth Scan for OS detection. The results were amazing. Check the picture..Phewww,,,,,,,
It revealed the most IMPORTANT results as far as an experienced hacker is concerned. It was shown that there was no Firewall protection for that system ,so when I asked my friend , it was true. Firewall wasnt enabled. This time he was a scapegoat , but all other times majority of Windows users and say a handful of Linux users become victim of attacks using such powerful tools.