Nmap 4.20

Nmap is a utility for network exploration or security auditing. It supports ping scanning (determine which hosts are up), many port scanning techniques (determine what services the hosts are offering), version detection (determine what application/service is runing on a port), and TCP/IP fingerprinting (remote host OS or device identification).
Nmap project also offers flexible target and port specification, decoy/stealth scanning, SunRPC scanning, and more. Most Unix and Windows platforms are supported in both GUI and command line modes. Several popular handheld devices are also supported, including the Sharp Zaurus and the iPAQ.
Main features:
- Flexible: 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. See the documentation page.
- Powerful: Nmap has been used to scan huge networks of literally hundreds of thousands of machines.
- Portable: Most operating systems are supported, including Linux, Microsoft Windows, FreeBSD, OpenBSD, Solaris, IRIX, Mac OS X, HP-UX, NetBSD, Sun OS, Amiga, and more.
- Easy: While Nmap offers a rich set of advanced features for power users, you can start out as simply as "nmap -v -A targethost". Both traditional command line and graphical (GUI) versions are available to suit your preference. Binaries are available for those who do not wish to compile Nmap from source.
- Free: The primary goals of the Nmap Project is to help make the Internet a little more secure and to provide administrators/auditors/hackers with an advanced tool for exploring their networks. Nmap is available for free download, and also comes with full source code that you may modify and redistribute under the terms of the GNU General Public License (GPL).
- Well Documented: Significant effort has been put into comprehensive and up-to-date man pages, whitepapers, and tutorials. Find them in multiple languages here.
- Supported: While Nmap comes with no warranty, you can write the author (fyodor@insecure.org) if you experience any problems. We also host several mailing lists you can join.
- Acclaimed: Nmap has won numerous awards, including "Information Security Product of the Year" by Linux Journal, Info World and Codetalker Digest. It has been featured in hundreds of magazine articles and is even recommended by Microsoft. Visit the press page for further details.
- Popular: Thousands of people download Nmap every day, and it is included with many operating systems (Redhat Linux, Debian Linux, Gentoo, FreeBSD, OpenBSD, etc). It is among the top ten (out of 30,000) programs at the Freshmeat.Net repository. This is important because it lends Nmap its vibrant development and user support communities.