The Nmap Security Scanner is (C) 1996–2022 Nmap Software LLC ("The Nmap Project"). Nmap is also a registered trademark of the Nmap Project. It is published under the Nmap Public Source License. This generally allows end users to download and use Nmap for free. It doesn't allow Nmap to be used and redistributed within commercial software or hardware products (including appliances, virtual machines, and traditional applications). We fund the project by selling a special Nmap OEM Edition for this purpose, as described at https://nmap.org/oem. Hundreds of large and small software vendors have already purchased OEM licenses to embed Nmap technology such as host discovery, port scanning, OS detection, version detection, and the Nmap Scripting Engine within their products.

The Nmap Project has permission to redistribute Npcap, a packet capturing driver and library for the Microsoft Windows platform. Npcap is a separate work with it's own license rather than this Nmap license. Since the Npcap license does not permit redistribution without special permission, our Nmap Windows binary packages which contain Npcap may not be redistributed without special permission.

Even though the NPSL is based on GPLv2, it contains different provisions and is not directly compatible. It is incompatible with some other open source licenses as well. In some cases we can relicense portions of Nmap or grant special permissions to use it in other open source software. Please contact fyodor@nmap.org with any such requests. Similarly, we don't incorporate incompatible open source software into Nmap without special permission from the copyright holders.

If you have received a written license agreement or contract for Nmap (such as an Nmap OEM license) stating terms other than these, you may choose to use and redistribute Nmap under those terms instead.

This Nmap Reference Guide is (C) 2005–2022 Nmap Software LLC. It is hereby placed under version 3.0 of the Creative Commons Attribution License. This allows you redistribute and modify the work as you desire, as long as you credit the original source. Alternatively, you may choose to treat this document as falling under the same license as Nmap itself (discussed previously).

Source is provided to this software because we believe users have a right to know exactly what a program is going to do before they run it. This also allows you to audit the software for security holes.

Source code also allows you to port Nmap to new platforms, fix bugs, and add new features. You are highly encouraged to submit your changes as Github Pull Requests (PR) or send them to <dev@nmap.org> for possible incorporation into the main distribution. By submitting such changes, it is assumed that you are offering the Nmap Project the unlimited, non-exclusive right to reuse, modify, and relicense the code. This is important because the inability to relicense code has caused devastating problems for other Free Software projects (such as KDE and NASM). We also sell commercial licenses to Nmap OEM. If you wish to specify special license conditions of your contributions, just say so when you send them.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

It should also be noted that Nmap has occasionally been known to crash poorly written applications, TCP/IP stacks, and even operating systems. While this is extremely rare, it is important to keep in mind. Nmap should never be run against mission critical systems unless you are prepared to suffer downtime. We acknowledge here that Nmap may crash your systems or networks and we disclaim all liability for any damage or problems Nmap could cause.

Because of the slight risk of crashes and because a few black hats like to use Nmap for reconnaissance prior to attacking systems, there are administrators who become upset and may complain when their system is scanned. Thus, it is often advisable to request permission before doing even a light scan of a network.

Nmap should never be installed with special privileges (e.g. suid root). That would open up a major security vulnerability as other users on the system (or attackers) could use it for privilege escalation.

Nmap is not designed, manufactured, or intended for use in hazardous environments requiring fail- safe performance where the failure of the software could lead directly to death, personal injury, or significant physical or environmental damage.

This product includes software developed by the Apache Software Foundation. A modified version of the Libpcap portable packet capture library is distributed along with Nmap. The Windows version of Nmap utilizes the Libpcap-derived Ncap library instead. Regular expression support is provided by the PCRE library, which is open-source software, written by Philip Hazel. Certain raw networking functions use the Libdnet networking library, which was written by Dug Song. A modified version is distributed with Nmap. Nmap can optionally link with the OpenSSL cryptography toolkit for SSL version detection support. The Nmap Scripting Engine uses an embedded version of the Lua programming language. The Liblinear linear classification library is used for our IPv6 OS detection machine learning techniques (see the section called “IPv6 matching”). All of the third-party software described in this paragraph is freely redistributable under BSD-style software licenses.

Binary packages for Windows and Mac OS X include support libraries necessary to run Zenmap and Ndiff with Python and PyGTK. (Unix platforms commonly make these libraries easy to install, so they are not part of the packages.) A listing of these support libraries and their licenses is included in the LICENSES files.

This software was supported in part through the Google Summer of Code and the DARPA CINDER program (DARPA-BAA-10-84).

Nmap only uses encryption when compiled with the optional OpenSSL support and linked with OpenSSL. When compiled without OpenSSL support, the Nmap Project believes that Nmap is not subject to U.S. Export Administration Regulations (EAR) export control. As such, there is no applicable ECCN (export control classification number) and exportation does not require any special license, permit, or other governmental authorization.

When compiled with OpenSSL support or distributed as source code, the Nmap Project believes that Nmap falls under U.S. ECCN 5D002 (“Information Security Software”). We distribute Nmap under the TSU exception for publicly available encryption software defined in EAR 740.13(e).