What is NMap?

Using NMap on Unix-Based Systems

Using Nmap on Microsoft Windows

What is NMap?

Network Mapper, or NMap for short, is a security scanner used to evaluate the security of target computers, and to discover services on a computer network. It is commonly used for:

• Auditing the security of a computer, by identifying the network connections which can be made to it
• Identifying open ports on a target computer to expose vulnerabilities to attacks
• Network inventory, maintenance, and asset management
• Auditing the security of a network, by identifying unexpected new servers

Using NMap On Unix-Based Systems

Initial Installation

Many Unix-based operating systems (i.e. Linux and Solaris) include NMap as part of their initial install package. If this software is bundled together we recommend using the factory installation and documentation.

Live Linux Distros (bootable Linux CDs) like the Network Security Toolkit also have NMap preinstalled.

Using NMap

Type in the following command at the command line to execute a simple scan with Nmap:

nmap [options] [hostname(s)]

Where hostname is the name or IP address of the host(s) to be scanned. You can try a scan on the following host as a test:

nmap scanme.nmap.org

You may also add options to the command line. Some common options include:

-A Enable detection of Operating System and version
-T4 Faster execution of scan
-v Verbose mode

Typing nmap by itself on the command line will give a list of options. A complete list and explanation of options can be found at this page: http://insecure.org/nmap/man/

Click here to view a video overview and tutorial of NMap's command line interface (Flash is required).

There is also a graphical front-end for Nmap, entitled NmapFE. You can start NmapFE from an X-Windows session. The interface works similarly to the command line version.

Using Nmap on Microsoft Windows

Initial Installation

The Windows version of NMap version 4.2 can be downloaded here: http://download.insecure.org/nmap/dist/nmap-4.20-setup.exe

Run this file and the installer will walk you through the setup process.

This installs a command-line version of NMap that is run from a command prompt.

Using Nmap

Make sure the user you are logged in as has administrative privileges in the computer (should be in the administrators group).

1. Open a command/DOS Window, by selecting Start -> Run and type cmd<enter>.

2. Change to the directory you installed Nmap into. Assuming you used the default path, type the following commands.

c:
cd "\Program Files\Nmap"

From here you can execute Nmap as detailed in the Unix command line instructions.

An example of an NMap scan (running from a Windows command prompt)

If you prefer a graphical interface, you may download this unofficial front-end for NMap:
http://www.syhunt.com/getapp.php?name=nmapw&c=6009357f1afabf0b8138a20405710a0f