Nmap Public Source License

Nmap is distributed under the terms of the Nmap Public Source License (annotated HTML version / plain text version). This license is based on the GNU GPLv2, but with important additional terms, conditions, clarifications and exceptions. It also contains a warranty disclaimer and contributor agreement. We believe it is compliant with the Open Source Definition, but we haven't gone through their certification process (which requires an attorney).

The primary goals of this license are:

• Keep Nmap free for the millions of individuals and organizations who depend on it.
• Prohibit redistribution and use of Nmap within proprietary hardware and software products. This is because we fund the Nmap Project by selling a special Nmap OEM license for companies that wish to embed Nmap technology within their products. Nmap OEM also includes commercial support, indemnification, and custom Windows builds.
• Keep the Nmap source code available for public review. This helps people understand how Nmap works and evaluate Nmap for security and code quality. Users are even encouraged to submit patches that improve Nmap further.

The license itself is rather terse, so we have created the Annotated HTML Nmap Public Source License. This version includes further reasoning behind and explanations of the license terms. These annotations are not a legal document or legal advice. If you need to know exactly what the license requires, you need to read and understand the license itself; if you need legal advice, talk to a lawyer.

Note that some releases of Nmap may fall under a previous version of this license, or a different license entirely. The exact terms for a given version of Nmap can be found in the included LICENSE or COPYING file. To ease the transition to the NPSL, the first three Nmap releases made under that license (Nmap 7.90, 7.91, and 7.92) may also be used under the previous Nmap license terms by anyone who prefers those.