Nmap is a utility for port scanning large networks, although it works fine for single hosts. Sometimes you need speed, other times you may need stealth. In some cases, bypassing firewalls may be required. Not to mention the fact that you may want to scan different protocols (UDP, TCP, ICMP, etc.). Nmap supports Vanilla TCP connect() scanning, TCP SYN (half open) scanning, TCP FIN, Xmas, or NULL (stealth) scanning, TCP ftp proxy (bounce attack) scanning, SYN/FIN scanning using IP fragments (bypasses some packet filters), TCP ACK and Window scanning, UDP raw ICMP port unreachable scanning, ICMP scanning (ping-sweep), TCP Ping scanning, Direct (non portmapper) RPC scanning, Remote OS Identification by TCP/IP Fingerprinting, and Reverse-ident scanning. Nmap also supports a number of performance and reliability features such as dynamic delay time calculations, packet timeout and retransmission, parallel port scanning, detection of down hosts via parallel pings.
Nmap is …
- 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 license.
- Well Documented: Significant effort has been put into comprehensive and up-to-date man pages, whitepapers, tutorials, and even a whole book! Find them in multiple languages here.
- Supported: While Nmap comes with no warranty, it is well supported by a vibrant community of developers and users. Most of this interaction occurs on the Nmap mailing lists. Most bug reports and questions should be sent to the nmap-dev list, but only after you read the guidelines. We recommend that all users subscribe to the low-traffic nmap-hackers announcement list. You can also find Nmap on Facebook and Twitter. For real-time chat, join the #nmap channel on Freenode or EFNet.
- 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, several movies, dozens of books, and one comic book series. Visit the press pagefor 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.
Changelog Nmap 6.47:
o Integrated all of your IPv4 OS fingerprint submissions since June 2013
(2700+ of them). Added 366 fingerprints, bringing the new total to 4485.
Additions include Linux 3.10 - 3.14, iOS 7, OpenBSD 5.4 - 5.5, FreeBSD 9.2,
OS X 10.9, Android 4.3, and more. Many existing fingerprints were improved.
Highlights: http://seclists.org/nmap-dev/2014/q3/325 [Daniel Miller]
o (Windows, RPMs) Upgraded the included OpenSSL to version 1.0.1i. [Daniel Miller]
o (Windows) Upgraded the included Python to version 2.7.8. [Daniel Miller]
o Removed the External Entity Declaration from the DOCTYPE in Nmap's XML. This
was added in 6.45, and resulted in trouble for Nmap XML parsers without
network access, as well as increased traffic to Nmap's servers. The doctype
o [Ndiff] Fixed the installation process on Windows, which was missing the
actual Ndiff Python module since we separated it from the driver script.
o [Ndiff] Fixed the ndiff.bat wrapper in the zipfile Windows distribution,
which was giving the error, "Microsoft was unexpected at this time." See
https://support.microsoft.com/kb/2524009 [Daniel Miller]
o [Zenmap] Fixed the Zenmap .dmg installer for OS X. Zenmap failed to launch,
producing this error:
Could not import the zenmapGUI.App module:
Library not loaded: /Users/david/macports-10.5/lib/libffi.5.dylibn
Reason: image not found'.
o [Ncat] Fixed SOCKS5 username/password authentication. The password length was
being written in the wrong place, so authentication could not succeed.
Reported with patch by Pierluigi Vittori.
o Avoid formatting NULL as "%s" when running nmap --iflist. GNU libc converts
this to the string "(null)", but it caused segfault on Solaris. [Daniel Miller]
o [Zenmap][Ndiff] Avoid crashing when users have the antiquated PyXML package
installed. Python tries to be nice and loads it when we import xml, but it
isn't compatible. Instead, we force Python to use the standard library xml
module. [Daniel Miller]
o Handle ICMP admin-prohibited messages when doing service version detection.
Crash reported by Nathan Stocks was: Unexpected error in NSE_TYPE_READ
callback. Error code: 101 (Network is unreachable) [David Fifield]
o [NSE] Fix a bug causing http.head to not honor redirects. [Patrik Karlsson]
o [Zenmap] Fix a bug in DiffViewer causing this crash:
TypeError: GtkTextBuffer.set_text() argument 1 must be string or read-only
buffer, not NmapParserSAX
Crash happened when trying to compare two scans within Zenmap. [Daniel Miller]