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Nmap Security Scanner
Nmap scan results
Nmap scan results
Original author(s) Gordon Lyon (Fyodor)
Initial release September 1997; 21 years ago (1997-09)
Stable release
7.70 / 21 March 2018; 5 months ago (2018-03-21)[1]
Repository Edit this at Wikidata
Written in C, C++, Python, Lua
Operating system Cross-platform
Available in English
Type computer security, network management
License modified GPL v2

Nmap (Network Mapper) is a free and open-source security scanner, originally written by Gordon Lyon (also known by his pseudonym Fyodor Vaskovich),[2] used to discover hosts and services on a computer network, thus building a "map" of the network. To accomplish its goal, Nmap sends specially crafted packets to the target host(s) and then analyzes the responses.

The software provides a number of features for probing computer networks, including host discovery and service and operating-system detection. These features are extensible by scripts that provide more advanced service detection,[3] vulnerability detection,[3] and other features. Nmap can adapt to network conditions including latency and congestion during a scan. The Nmap user community continues to develop and refine the tool.

Nmap started as a Linux-only utility,[4] but porting to Windows, Solaris, HP-UX, BSD variants (including macOS), AmigaOS, and IRIX have followed.[5] Linux is the most popular platform, followed closely by Windows.[6]


Nmap features include:

  • Host discovery – Identifying hosts on a network. For example, listing the hosts that respond to TCP and/or ICMP requests or have a particular port open.
  • Port scanning – Enumerating the open ports on target hosts.
  • Version detection – Interrogating network services on remote devices to determine application name and version number.[7]
  • OS detection – Determining the operating system and hardware characteristics of network devices.
  • Scriptable interaction with the target – using Nmap Scripting Engine[8] (NSE) and Lua programming language.

Nmap can provide further information on targets, including reverse DNS names, device types, and MAC addresses.[9]

Typical uses of Nmap:

  • Auditing the security of a device or firewall by identifying the network connections which can be made to, or through it.[10]
  • Identifying open ports on a target host in preparation for auditing.[11]
  • Network inventory, network mapping, maintenance and asset management.
  • Auditing the security of a network by identifying new servers.[12]
  • Generating traffic to hosts on a network, response analysis and response time measurement.[13]
  • Finding and exploiting vulnerabilities in a network.[14]
  • DNS queries and subdomain search

Graphical interfaces

NmapFE, originally written by Zach Smith, was Nmap's official GUI for Nmap versions 2.2 to 4.22.[15] For Nmap 4.50 (originally in the 4.22SOC development series) NmapFE was replaced with Zenmap, a new official graphical user interface based on UMIT, developed by Adriano Monteiro Marques.

Various web-based interfaces allow controlling Nmap or analysing Nmap results from a web browser. These include Nmap-CGI,[16] and IVRE.[17]

Microsoft Windows specific GUIs exist, including NMapWin,[18] which has not been updated since June 2003 (v1.4.0), and NMapW[19] by Syhunt.

Reporting results

Nmap provides four possible output formats. All but the interactive output is saved to a file. Nmap output can be manipulated by text processing software, enabling the user to create customized reports.[20]

presented and updated real time when a user runs Nmap from the command line. Various options can be entered during the scan to facilitate monitoring.
a format that can be further processed by XML tools. It can be converted into a HTML report using XSLT.
output that is tailored to line-oriented processing tools such as grep, sed or awk.
the output as seen while running Nmap from the command line, but saved to a file.
Script kiddie
meant to be an amusing way to format the interactive output replacing letters with their visually alike number representations. For example, Interesting ports becomes Int3rest1ng p0rtz.


Nmap was first published in September 1997, as an article in Phrack Magazine with source-code included.[21] With help and contributions of the computer security community, development continued. Enhancements included operating system fingerprinting, service fingerprinting,[7] code rewrites (C to C++), additional scan types, protocol support (e.g. IPv6, SCTP[22]) and new programs that complement Nmap's core features

Major releases include:[15]

Date Version Significance
12 December 1998 Nmap 2.00 Nmap 2.00 is released, including Operating System fingerprinting[23]
11 April 1999 NmapFE A GTK+ front end, is bundled with Nmap[23]
7 December 2000 Windows port[15]
28 August 2002 Rewrite from C to C++[15]
16 September 2003 The first public release to include service version detection[15]
31 August 2004 Nmap 3.70 Core scan engine rewritten for version 3.70. New engine is called ultra_scan[24]
Summer 2005 Nmap selected for participation in Google Summer of Code.[25] Added features included Zenmap, Nmap Scripting Engine (NSE), Ncat, and 2nd-generation OS detection.
13 December 2007 Nmap 4.50 Nmap 4.50, the 10th Anniversary Edition, was released. Included Zenmap, 2nd-generation OS detection, and the Nmap Scripting Engine[26]
30 March 2009 Nmap 4.85BETA5 Emergency release of Nmap 4.85BETA5, leveraging NSE to detect Conficker infections[27]
16 July 2009 Nmap 5.00 Included netcat-replacement Ncat and Ndiff scan comparison tool[28]
28 January 2011 Nmap 5.50 Included Nping packet generation response analysis and response time measurement[29][30]
21 May 2012 Nmap 6.00 Released with full IPv6 support.[citation needed]
November 9, 2015; 2 years ago (2015-11-09) Nmap 7.00 [31]
December 20, 2016; 20 months ago (2016-12-20) Nmap 7.40
March 20, 2018; 6 months ago (2018-03-20) Nmap 7.70 [32]

Ethical issues and legality

Nmap is a tool that can be used to discover services running on Internet connected systems. Like any tool it could potentially be used for black hat hacking,[33] as a precursor to attempts to gain unauthorized access to computer systems; however, Nmap is also used by security and systems administration to assess their own networks for vulnerabilities (i.e. white hat hacking).

System administrators can use Nmap to search for unauthorized servers, or for computers that do not conform to security standards.[34]

Nmap is related to vulnerability assessment tools such as Nessus, which test for common vulnerabilities in open ports. The included NSE[35] scripts that are packaged with modern versions of Nmap are able to perform vulnerability checks against discovered services.

In some jurisdictions, unauthorized port scanning is illegal.[36]


Nmap was originally distributed under the GNU Public License (GPL)[21]. In later releases, Nmap's authors added clarifications and specific interpretations to the license where they felt the GPL was unclear or lacking.[37] For instance, Nmap 3.50 specifically revoked the license of SCO Group to distribute Nmap software because of their views on the SCO-Linux controversies.[38]

In popular culture

In The Matrix Reloaded, Trinity is seen using Nmap to access a power plant's computer system,[39] allowing Neo to "physically" break in to a building. The appearance of Nmap in the film was widely discussed on Internet forums and hailed as an unusually realistic example of hacking.[40]

Nmap and NmapFE were used in The Listening, a 2006 movie about a former NSA officer who defects and mounts a clandestine counter-listening station high in the Italian alps.

Nmap source code can be seen in the movie Battle Royale, as well as brief views of the command line version of Nmap executing in Live Free or Die Hard and Bourne Ultimatum.[39] In 2013, Nmap continued to make appearances in movies including popular sci-fi movie Elysium.

The film Dredd, a film adaptation of the famous Judge Dredd comics, was released in 2012 and also contains multiple Nmap scenes.[39] Nmap is used for network reconnaissance and exploitation of the slum tower network. It is even seen briefly in the movie's trailer.

The command Nmap is widely used in the video game Hacknet, allowing to probe the network ports of a target system to hack it.

In academia

Nmap is an integral part of academic activities. It has been used for research involving the TCP/IP protocol suite and networking in general.[41] As well as being a research tool, Nmap has become a research topic.[42]

Sample output

$ nmap -A
Starting Nmap 6.47 ( ) at 2014-12-29 20:02 CET
Nmap scan report for (
Host is up (0.16s latency).
Not shown: 997 filtered ports
22/tcp   open  ssh        OpenSSH 5.3p1 Debian 3ubuntu7.1 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey:
|   1024 8d:60:f1:7c:ca:b7:3d:0a:d6:67:54:9d:69:d9:b9:dd (DSA)
|_  2048 79:f8:09:ac:d4:e2:32:42:10:49:d3:bd:20:82:85:ec (RSA)
80/tcp   open  http       Apache httpd 2.2.14 ((Ubuntu))
|_http-title: Go ahead and ScanMe!
9929/tcp open  nping-echo Nping echo
Warning: OSScan results may be unreliable because we could not find at least 1 open and 1 closed port
Device type: general purpose|phone|storage-misc|WAP
Running (JUST GUESSING): Linux 2.6.X|3.X|2.4.X (94%), Netgear RAIDiator 4.X (86%)
OS CPE: cpe:/o:linux:linux_kernel:2.6.38 cpe:/o:linux:linux_kernel:3 cpe:/o:netgear:raidiator:4 cpe:/o:linux:linux_kernel:2.4
Aggressive OS guesses: Linux 2.6.38 (94%), Linux 3.0 (92%), Linux 2.6.32 - 3.0 (91%), Linux 2.6.18 (91%), Linux 2.6.39 (90%), Linux 2.6.32 - 2.6.39 (90%), Linux 2.6.38 - 3.0 (90%), Linux 2.6.38 - 2.6.39 (89%), Linux 2.6.35 (88%), Linux 2.6.37 (88%)
No exact OS matches for host (test conditions non-ideal).
Network Distance: 13 hops
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

TRACEROUTE (using port 80/tcp)
1   14.21 ms
2   5.27 ms (
3   13.16 ms (
4   6.83 ms (
5   8.30 ms (
6   9.42 ms (
7   24.56 ms (
8   30.60 ms (
9   93.54 ms (
10  181.14 ms (
11  169.54 ms (
12  164.58 ms (
13  164.32 ms (

OS and Service detection performed. Please report any incorrect results at .
Nmap done: 1 IP address (1 host up) scanned in 28.98 seconds

See also


  1. ^ "Nmap Change Log". 2018-03-21. Retrieved 2018-03-22. 
  2. ^ "Matrix mixes life and hacking". BBC News. 2003-05-19. Retrieved 2009-01-14. 
  3. ^ a b Nmap Scripting Engine. Retrieved on 2013-02-01.
  4. ^ The History and Future of Nmap. Retrieved on 2013-02-01.
  5. ^ Other Platforms. Retrieved on 2013-02-01.
  6. ^ "Nmap Installation for Windows". Retrieved 2008-05-14. 
  7. ^ a b Service and Application Version Detection
  8. ^ []
  9. ^ "Chapter 15. Nmap Reference Guide". 2011-03-25. Retrieved 2011-04-23. 
  10. ^ Nmap Overview and Demonstration.
  11. ^ When Good Scanners Go Bad, From [1], ComputerWorld 22 March 1999
  12. ^ nmap-audit – Network auditing with Nmap.
  13. ^ Nping - Network packet generation tool / ping utility.
  14. ^ Leyden, John. "Revealed ... GCHQ's incredible hacking tool to sweep net for vulnerabilities: Nmap". The Register. Retrieved 14 December 2014. 
  15. ^ a b c d e "Nmap Change Log". Retrieved 2011-09-17. 
  16. ^ nmap-cgi homepage. Retrieved on 2011-09-17.
  17. ^ IVRE homepage.
  18. ^ NMapWin v1.2.3. Retrieved on 2011-09-17.
  19. ^ Syhunt Technology: Web Application Security and Testing Tools. (2010-10-23). Retrieved on 2011-09-17.
  20. ^ Output. Retrieved on 2011-12-10.
  21. ^ a b Nmap Introduction – Phrack 51, Article 11. Retrieved on 2011-09-17.
  22. ^ SCTP Support for Nmap. (2007-01-26). Retrieved on 2011-09-17.
  23. ^ a b "The History and Future of Nmap". 
  24. ^ "Nmap Hackers—Nmap 3.70 Released—Core Scan Engine Rewrite!". Retrieved 2011-09-17. 
  25. ^ "Google sponsors Nmap summer student developers". Retrieved 2011-09-17. 
  26. ^ "Nmap 4.50 Press Release". Retrieved 2011-09-17. 
  27. ^ "Nmap Development—Nmap 4.85BETA5—Now with Conficker detection!". Retrieved 2011-09-17. 
  28. ^ "Nmap 5.00 Release Notes". Retrieved 2011-09-17. 
  29. ^ "Nmap 5.50—Now with Gopher protocol support!". Retrieved 2011-09-17. 
  30. ^ []
  31. ^ []
  32. ^ []
  33. ^ "Hacking tool reportedly draws FBI subpoenas". 2004-11-24. Retrieved 2011-09-17. 
  34. ^ "120 – How to conduct a security audit" (PDF). Tech Support Alert. Retrieved 2011-09-17. 
  35. ^ "NSE scripts with brief summaries". Retrieved 2014-01-12. 
  36. ^ "First ruling by the Supreme Court of Finland on attempted break-in". Osborne Clarke. 2003. Retrieved 2010-02-21. 
  37. ^ "Nmap license terms". Retrieved 2018-03-22. 
  38. ^ "Nmap 3.50 Press Release". Retrieved 2018-02-21. 
  39. ^ a b c "nmap in the movies". 
  40. ^ Kevin Poulsen (2003-05-16). "Matrix Sequel Has Hacker Cred". The Register. 
  41. ^ "Validation of Sensor Alert Correlators" (PDF). 
  42. ^ "A Data Mining Based Analysis of Nmap Operating System Fingerprint Database". 


External links