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The DFSG and Software Licenses

This page is designed to be a first stop if you're making a new package and are not sure about whether its license allows it to meet the DebianFreeSoftwareGuidelines. Feel free to add licenses, with a link to their text and -- if possible -- a link to a related message in the DebianLegal archive or link to example packages in main which ship files licensed under this specific license. There is a licenses page on Debian's website too now: http://www.debian.org/legal/licenses/

Some of the licenses listed here are linked to the http://opensource.org/ site. If you find a link to the license on the original site, feel free to change it.

Please be aware that this page is not definitive and is intended to be an informational summary for packagers. http://www.debian.org/legal/licenses/ is somewhat more definitive, but is still not comprehensive. Licenses may be listed here that are not listed there, and vice versa. The decision on what licenses are acceptable is normally taken by the ftp team after project discussion, and may be the subject of project General Resolutions, but in most cases the presence of the license in the archive is the best indication that it's acceptable. There is not, at present, any completely definitive list of what licenses Debian does or does not accept.

The sections on this page are:


  1. The DFSG and Software Licenses
    1. DFSG-compatible Licenses
        1. Example packages
      2. The Artistic License
      3. The Apache Software License (ASL)
      4. The BSD-3-clause License
      5. Creative Commons Attribution Share-Alike (CC-BY-SA) v4.0
        1. Example packages
      6. Creative Commons Attribution Share-Alike (CC-BY-SA) v3.0
        1. Example packages
      7. Creative Commons Attribution unported (CC-BY) v3.0
        1. Example packages
      8. Creative Commons Attribution unported (CC-BY) v4.0
        1. Example packages
      9. Common Public License (CPL), Version 1.0
      10. IBM Public License, Version 1.0
      11. Eclipse Public License - 1.0
        1. Example packages
      12. The GNU General Public License (GPL)
      13. The GNU Lesser General Public License (LGPL)
      14. The MIT License
        1. Example packages
        2. Consequences
      15. The SIL Open Font License
        1. Example packages
      16. Mozilla Public License (MPL)
        1. Example packages
      18. The zlib/libpng License (Zlib)
        1. Example packages
    2. Other DFSG compatible licenses
      1. ISC license
      2. The MirOS Licence
    3. Licenses whose status is unsettled
      1. Q Public License (QPL), Version 1.0
      2. X-Oz License
      3. Licence Art Libre (Free Art License)
    4. Licenses that are DFSG-incompatible
      1. Apple Public Source License (APSL)
      2. GNU Free Documentation License (GFDL)
        1. Exception
      3. Open Publication License (OPL) v1.0
      4. Open Software License (OSL) v1.1
      5. Creative Commons Attribution License (CC-by), v1.0
      6. Creative Commons Attribution-Non Commercial-Share Alike (CC-by-nc-sa)
      7. Creative Commons Attribution-Share Alike Generic (CC-BY-SA), v1.0
      8. Creative Commons Sampling Plus (CC-sampling+), v1.0
      9. JSON evil license
      10. License for OpenPBS and Torque
      11. Swiss Ephemeris Public License
      12. RealNetworks Public Source License (RPSL)
      13. SPIN License
      14. Common Public Attribution License
    5. More Resources
      1. Public Domain
      2. A note on terminology
      3. If the license isn't on this list

DFSG-compatible Licenses

All DFSG-compatible licenses. If a license is missing, please create a new paragraph similar to the existing ones and sort the licenses in alphabetical order.

A simple way to determine how many packages ship a specific license is to use codesearch.debian.net:

For instance use

  • AGPL path:debian/copyright

as search query for the AGPL license.


DFSG-free license.


Example packages

The Artistic License


Perl is licensed under the Artistic License.

Do note that the Artistic License is considered non-free by the FSF. They suggest to use the Clarified Artistic License (also called Artistic License 2.0) instead. However, the original Artistic License is still considered DFSG-free.

The Apache Software License (ASL)


The Apache web server is distributed under the ASL. The current version of the ASL is 2.0.

Older versions of the Apache License (1.0 and 1.1) are also DFSG free, but the Apache Software Foundation recommends using the Apache 2.0 license instead.


The BSD-3-clause License


(This is distinct from the original, 4-clause BSD license that included an advertising requirement. The original license is now deprecated even by the BSD project.)

The BSD operating system, and many utilities that come from it, are licensed under the 3-clause BSD license.

Note that a 2-clause form of the BSD license, removing the third condition, is also in use. This is because even a generous copyright license does not implicitly forfeit the copyright holder's "right of publicity". In other words, even if a license does not forbid you from claiming that the copyright holder or other parties endorses or promotes your work, the law generally does. We're not aware of any exceptions.

Creative Commons Attribution Share-Alike (CC-BY-SA) v4.0

Version 4.0 is considered to be compatible to the DFSG. Changes from the previous version are discussed in a thread starting at https://lists.debian.org/3172728.oiOx47Q9HF@debstor

Example packages

Creative Commons Attribution Share-Alike (CC-BY-SA) v3.0

In contrast to the CC-SA 1.0 license, version 3.0 is considered to be compatible to the DFSG. In addition, the version 2.0 and 2.5 are NOT transitively compatible because of clause 4b, since that only allows redistribution of derivative works under later versions of the license.

Example packages

Creative Commons Attribution unported (CC-BY) v3.0

DFSG-free license.


Example packages

Creative Commons Attribution unported (CC-BY) v4.0

DFSG-free license.


Example packages

Common Public License (CPL), Version 1.0

See the IBM Public License, immediately below.

IBM Public License, Version 1.0

This license was later renamed the Common Public License (CPL). It is used for OpenAFS and Postfix and has been accepted in Debian main since 2000.

Eclipse Public License - 1.0

DFSG-free license.


Example packages

The GNU General Public License (GPL)


This is the most popular free software license. Most of Linux (the kernel) is distributed under the GPL, as is most of the other basic software in the GNU operating system.

The GNU Lesser General Public License (LGPL)


(Earlier called the "Library General Public License"; this name is deprecated because it confuses the license's intent.)

The GNU C library is distributed under the LGPL.

The MIT License


The shortest one. Learn it by heart if you write a lot of scripts :-)

Most of the X Window System is distributed under the MIT License.

Example packages

Exception : The University of Washington's interpretation of the MIT License, as the University interprets it for the pine email client, does not follow the DFSG. See the DebianFreeSoftwareGuidelinesDraftFAQ.


pine is not part of Debian.

The SIL Open Font License


The following restriction on distributions, which is part of OFL, has been widely accepted by open source projects when it is applied to fonts:

  • 1) Neither the Font Software nor any of its individual components, in Original or Modified Versions, may be sold by itself.


Example packages

Mozilla Public License (MPL)


The MPL is a DFSG-free license, which is suitable for Debian main. http://lists.debian.org/debian-legal/2007/07/msg00197.html http://lists.debian.org/debian-legal/2007/07/msg00215.html


DFSG-free license.


Example packages

The zlib/libpng License (Zlib)

DFSG-free license.


Example packages

Other DFSG compatible licenses

ISC license

The MirOS Licence

Licenses whose status is unsettled

Works under licenses in this group are not (yet?) accepted into debian main. This may change.

Q Public License (QPL), Version 1.0

The DFSG-freeness of this license has been called into question. Some people appear to believe that because the Qt library is in Debian main, that the QPL is DFSG-free. That is a hasty conclusion, however, because the Qt library is also licensed under the GNU GPL (see http://www.trolltech.com/newsroom/announcements/00000043.html).

The QPL is not GPL-compatible, which, regardless of one's opinion about the license's DFSG-freeness, poses a major practical problem for any code licensed under the QPL that is reused elsewhere in conjunction with code under the GNU GPL. This makes the QPL alone a particularly poor choice of license for a library.

Furthermore, it is not clear that the Trolltech corporation (the author of the Qt library and the QPL itself) believes the QPL to be a free software license. Trolltech's website describes how their dual-license approach is intended to be "open source-friendly" (see http://www.trolltech.com/company/model.html). If Trolltech felt that the QPL alone were friendly enough to open-source, why do they have a dual-licensing policy?

Copyright holders in QPL-licensed works should be encouraged to follow Trolltech's example, and dual-license their work under the GNU GPL or another clearly DFSG-free license.

X-Oz License

Only used by X-Oz Technologies, Inc.

This license's acceptance is stalled waiting for answers from a representative of X-Oz Technologies, Inc since April 2004.

Licence Art Libre (Free Art License)

Might not pass DissidentTest. Problems in the translation slow down approval to a halt.

Licenses that are DFSG-incompatible

These licenses seem impossible to use in a way that follows DFSG without significant exceptions/waivers.

Apple Public Source License (APSL)

GNU Free Documentation License (GFDL)


Open Publication License (OPL) v1.0

Open Software License (OSL) v1.1

Creative Commons Attribution License (CC-by), v1.0

It is believed that 2.0 still has problems (http://evan.prodromou.name/ccsummary/ccsummary.html), but it is under discussion between debian-legal and cc-licenses.

Creative Commons Attribution-Non Commercial-Share Alike (CC-by-nc-sa)

Creative Commons Attribution-Share Alike Generic (CC-BY-SA), v1.0

Creative Commons Sampling Plus (CC-sampling+), v1.0

JSON evil license

License for OpenPBS and Torque


Swiss Ephemeris Public License

This license is non free:

Upstream relicense under GPL

RealNetworks Public Source License (RPSL)

SPIN License

Common Public Attribution License

Issue: Badgeware license

Examples: Openproj, OpenEMM

More Resources


Public Domain

Public Domain could be a special case worth additional notes here.

A FAQ follows, extracted from:

Q: Since software "placed in the public domain" has no license isn't it not under a free software license, and therefore not acceptable as free software according to the DFSG?

A: Software placed in the public domain has all the freedoms required by the DFSG, and is free software.

Q: Public Domain in debian/copyright files? Example:

Copyright: John Doe

License: public-domain

These two statements seems to contradict each other: public domain means exactly the _absence_ of copyright.

A: The Copyright: field in this case is usually indicating who holds any residual copyright or author's rights in a jurisdiction which does not completely support public domain (PD). It also indicates who the individual was who dedicated the work to the PD.

Q: Specifically, public domain is _not_ open source

A: Public Domain works are not necessarily open source in all jurisdictions, but they can satisfy the DFSG in many.

Q: Since Debian is usually quite careful when it comes to legal issues, I'm wondering what the official view point is here?

A: The official viewpoint is that the software must meet the requirements of the DFSG. Generally, a CC0-style PD dedication is viewed as sufficient for all jurisdictions, and can satisfy the DFSG if source is available.

Q: Jurisdictions for Public Domain?

A: We are unaware of a case where a jurisdiction has upheld a copyright claim to a work which has been dedicated to the public domain everywhere. This is a potential theoretical source of problems, but there's enough actual problems with copyright and licensing for us to concentrate our limited time on them instead.

Q: Should there be a lintian error if the "license" is Public Domain and a copyright holder is specified?

A: No.

Q: Should Public Domain perhaps be prohibited in general?

A: Definitely not.

A note on terminology

Debian classifies software which has been packaged for it, in order to decide which section it should go in, if any. It is possible to use a DFSG-compatible license in a way that doesn't follow the DFSG, as pine shows. Anyone writing about a "free" or "non-free" license is probably abbreviating. That's not always a bad thing, but don't get confused by it.

Additionally, debian-legal contributors sometimes comment on licenses the list is asked about, because of ?ITPs or consultations. Those comments often include remarks about a term being "non-free" as a shorthand. Shorthands are good, but try not to get confused by it. debian-legal is not (and should not be turned into) FSF v2 or OSI v2.

If the license isn't on this list

If the license you're concerned about isn't on this short informal list, it may well have been discussed on debian-legal anyway. You can go to http://www.google.com/advanced_search; in the 'Domain' field, put in lists.debian.org. In the 'With all of the words' field, put in (at least) debian-legal. Then fill in the other fields as appropriate for searching for your license. Putting in a distinctive phrase from the license in the 'With the exact phrase' field is a good bet.