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
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 two Nmap
releases made under that license (Nmap 7.90 and 7.91) may also be used
Nmap license terms by anyone who prefers those.