The ISC license is a

permissive free software license A permissive software license, sometimes also called BSD-like or BSD-style license, is a free software, free-software software license, license which instead of copyleft protections, carries only minimal restrictions on how the software can be us ...

published by the Internet Software Consortium, now called Internet Systems Consortium (ISC). It is functionally equivalent to the simplified BSD and

MIT The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the m ...

licenses, but without language deemed unnecessary following the

Berne Convention The Berne Convention for the Protection of Literary and Artistic Works, usually known as the Berne Convention, was an international assembly held in 1886 in the Swiss city of Bern by ten European countries with the goal to agree on a set of leg ...

. Originally used for ISC software such as

BIND BIND () is a suite of software for interacting with the Domain Name System (DNS). Its most prominent component, named (pronounced ''name-dee'': , short for ''name daemon''), performs both of the main DNS server roles, acting as an authoritative ...

and dig, it has become the preferred license for contributions to

OpenBSD OpenBSD is a security-focused, free and open-source, Unix-like operating system based on the Berkeley Software Distribution (BSD). Theo de Raadt created OpenBSD in 1995 by forking NetBSD 1.0. According to the website, the OpenBSD project em ...

and the default license for npm packages. The ISC license is also used for

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which ...

wireless drivers contributed by

Qualcomm Atheros Qualcomm Atheros is a developer of semiconductor chips for network communications, particularly wireless chipsets. Founded under the name T-Span Systems in 1998 by experts in signal processing and VLSI design from Stanford University, the Un ...

License terms

When initially released, the license did not include the term " and/or", which was changed from "and" by ISC in 2007.

Paul Vixie Paul Vixie is an American computer scientist whose technical contributions include Domain Name System (DNS) protocol design and procedure, mechanisms to achieve operational robustness of DNS implementations, and significant contributions to open ...

stated on the BIND mailing list that the ISC license started using the term "and/or" to avoid controversy similar to the events surrounding the

University of Washington The University of Washington (UW, simply Washington, or informally U-Dub) is a public research university in Seattle, Washington. Founded in 1861, Washington is one of the oldest universities on the West Coast; it was established in Seattle a ...

's refusal to allow distribution of the

Pine A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accep ...

email software.

OpenBSD license

The OpenBSD project began using the ISC license in 2003, before ISC added the term "and/or".

Theo de Raadt Theo de Raadt (; ; born May 19, 1968) is a South African-born software engineer who lives in Calgary, Alberta, Canada. He is the founder and leader of the OpenBSD and OpenSSH projects and was also a founding member of NetBSD. In 2004, De Raadt wo ...

of OpenBSD chose to retain the wording originally used by the

University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public land-grant research university in Berkeley, California. Established in 1868 as the University of California, it is the state's first land-grant u ...

, which allowed free redistribution in either non-free or

open-source Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized sof ...

software. Both licenses are by the Free Software Foundation, and compatible with the

GNU GPL The GNU General Public License (GNU GPL or simply GPL) is a series of widely used free software licenses that guarantee end users the four freedoms to run, study, share, and modify the software. The license was the first copyleft for general us ...

Reception

In 2015, ISC announced they would release their Kea DHCP Software under the Mozilla Public License 2.0, stating, "There is no longer a good reason for ISC to have its own license, separate from everything else". They also preferred a copyleft license, stating, "If a company uses our software but improves it, we really want those improvements to go back into the master source". Throughout the following years, they re-licensed all ISC-hosted software, including BIND in 2016 and ISC DHCP Server in 2017. The Publications Office of the European Union advises using the MIT license instead of the ISC License in order to reduce

license proliferation License proliferation is the phenomenon of an abundance of already existing and the continued creation of new software licenses for software and software packages in the FOSS ecosystem. License proliferation affects the whole FOSS ecosystem neg ...

. The GNU project states the inclusion of "and/or" still allows the license to be interpreted as prohibiting distribution of modified versions. Although they state there is no reason to avoid software released under this license, they advise against using the license to keep the problematic language from causing trouble in the future.

Footnotes

References

External links