(sorry for the lame photo)

About:

Nmap (“Network Mapper”) is the best tool to scan large networks to determine which hosts are up and what services they are offering. Originally written by Fyodor Vaskovich (the pseudonim of Gordon Lyon). Nmap offers a number of advanced features with the new  Nmap Scripting Engine (NSE), the flexybility of the Lua programming language allow to write simple and powerful script to automate a wide variety of networking task. But about NSE we will talk another time, in this post I’m going to illustrate how to compile and install Nmap from the source code.

DISCLAIMER:
This tools can cause harm to the normal operation of your network/servers if used improperly. Use this tool on your own networks/servers, or networks/servers for which you have been given permission to test. Before using this tools, please read the documentation available.

Main Features:

* Host Discovery
* Port Scanning
* Version Detection
* OS Detection
* Scriptable interaction with the target

Installation (ubuntu 10.04 32 bit):

apt-get install build-essential checkinstall bzip2

wget http://nmap.org/dist/nmap-5.21.tar.bz2

bzip2 -cd nmap-5.21.tar.bz2 | tar xvf -

./configure  –without-zenmap

make

checkinstall

dpkg -i nmap_5.21-1_i386.deb

Testing nmap:

nmap -v -n -sS scanme.nmap.org

Starting Nmap 5.21 ( http://nmap.org ) at 2010-09-25 07:07 UTC
Initiating Ping Scan at 07:07
Scanning scanme.nmap.org (64.13.134.52) [4 ports]
Completed Ping Scan at 07:07, 0.21s elapsed (1 total hosts)
Initiating SYN Stealth Scan at 07:07
Scanning scanme.nmap.org (64.13.134.52) [1000 ports]
Discovered open port 22/tcp on 64.13.134.52
Discovered open port 80/tcp on 64.13.134.52
Discovered open port 53/tcp on 64.13.134.52
Completed SYN Stealth Scan at 07:07, 12.00s elapsed (1000 total ports)
Nmap scan report for scanme.nmap.org (64.13.134.52)
Host is up (0.21s latency).
Not shown: 993 filtered ports
PORT      STATE  SERVICE
22/tcp    open   ssh
25/tcp    closed smtp
53/tcp    open   domain
70/tcp    closed gopher
80/tcp    open   http
113/tcp   closed auth
31337/tcp closed Elite

Read data files from: /usr/local/share/nmap
Nmap done: 1 IP address (1 host up) scanned in 12.33 seconds
Raw packets sent: 2003 (88.084KB) | Rcvd: 16 (712B)

Happy scanning