Devilz Linux

Basic Scanning Overview   This section covers the basics of network scanning with Nmap. Before we begin it is important to understand the following concepts: Firewalls, routers, proxy servers, and other security devices can skew the results of an Nmap scan. Scanning remote hosts that are not on your local network may provide misleading information because of this. Some scanning options require elevated privileges. On Unix and Linux systems you may be required to login as the root user or to execute Nmap using the sudo command. There are also several warnings to take into consideration: Scanning networks that you do not have permission to scan can get you in trouble with your internet service provider, the police, and possibly even the government. Don’t go off scanning the FBI or Secret Service websites unless you want to get in trouble. Aggressively scanning some systems may cause them to crash which can lead to undesirable results like system downtime and data loss

Installing Nmap on Windows Step 1 Download the Windows version of Nmap from www.nmap.org . Step 2 Launch the Nmap setup program. Select the default installation (recommended) which will install the entire Nmap suite of utilities. Step 3 During installation, a helper program called WinPcap will also be installed. WinPcap is required for Nmap to function properly on the Windows platform so do not skip this step. Step 4 After the WinPcap installation has completed you are given the option to configure its service settings. The default options will enable the WinPcap service to start when Windows boots. This is recommended as Nmap will not function correctly when the WinPcap service is not running.  Step 5 Once Nmap has been successfully installed you can verify it is working correctly by executing nmap scanme.insecure.org on the command line (located in Start > Programs > Accessories > Command Prompt). C:\>nmap -h

Installing Nmap on Unix and Linux systems Most popular Linux distributions provide binary Nmap packages which allow for simple installation. Installation on Unix systems requires compiling Nmap from source code . At the time of this writing Nmap version 5.00 was not available for automatic installation on some Linux distributions. For many, installing Nmap via the popular apt or yum package managers will only install Note version 4.x. If your distribution already has Nmap 5.00 in their repositories you can install Nmap by using the commands listed below. Otherwise,  to install Nmap 5.00 from source code(steps are given down to instal nmap from source). Installing Precompiled Packages for Linux For Debian and Ubuntu based systems # apt-get install nmap For Red Hat and Fedora based systems # yum install nmap For Gentoo Linux based systems # emerge nmap To check which version of Nmap you are running, type the following command on the command line: # nmap -V Nmap