Nmap for linux- Free security scanner

Hi friends, Comment box says most of you have started using Linux or Ubuntu. So it is neccesary to know about network security and monitoring tools. I have used etherape, wireshark, Nmap and Tcpdump. Oh I forgot to tell you aboout the old ping command. But today we will talk about Nmap only. 
Nmap is a widly used security scaning tool, It is used for network exploration or security auditing. It uses a variety of special packets to probe a network for any number of purposes including creating an IP map of addresses, determining the operating system of a specific target IP address and probing a range of IP ports at a specific address. Nmap runs on all major computer operating systems, and official binary packages are avalable for Linux, Windows, and Mac OS X. In addition to the classic command-line Nmap executable, the Nmap suite includes an advanced GUI and results viewer (Zenmap), a flexible data transfer, redirection, and debugging tool (Ncat), and a utility for comparing scan results (Ndiff). It's a free, easy, powerfull and portable tool for network scanning.Supports dozens of advanced techniques for mapping out networks filled with IP filters, firewalls, routers, and other obstacles. This includes many port scanning mechanisms (both TCP & UDP), OS detection, version detection, ping sweeps, and more. Nmap 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.In addition to the interesting ports table, Nmap can provide further information on targets, including reverse DNS names, operating system guesses, device types, and MAC addresses.
Nmap is available for free download, and also comes with full source code that you may modify and redistribute under the terms of the license.

Nmap and Zenmap (the graphical front end) are available in several versions and formats. You can download Nmap from here

If you are using ubuntu there are many grafic user interface tools available in software centre that uses Nmap. For example Zenmap and NmapSI4

The proper upgrade/install command is apt-get install nmap.

Or you can download from here

Steps for converting Nmap RPM files to Debian/Ubuntu deb format for installation on Debian/Ubuntu

1. If you don't have the alien command, install it with a command such as sudo apt-get install alien
2. Download the Nmap RPMs for your platform (x86 or x86-64) from http://nmap.org/download.html. This description will use nmap-5.21-1.x86_64.rpm
3. Verify the download integrity as described in the section called “Verifying the Integrity of Nmap Downloads”.
4. Generate a Debian package with a command such as sudo alien nmap-5.21-1.x86_64.rpm
5. Install the Debian package with a command such as sudo dpkg --install nmap_5.21-2_amd64.deb
6. Steps 2–5 can be repeated for the other Nmap RPMs such as Zenmap, Ncat, and Nping.
   
   

To know more about Nmap you can read this guide or visit Nmap.org or wait for my next "Nmap commands" hacking Tutorial Article Help