FreeRadius licensing and distribution

Alan DeKok aland at
Fri Feb 23 09:46:21 CET 2007

devquest at wrote:
> I have a FreeRadius licensing/distribution question to which I have
> not been able to find a definitive answer in the archives.

  You can also see the FSF FAQ about the GPL.  Information on the GPL
license, including distribution, etc. is widely available.  There is
little in the way of discussions specific to FreeRADIUS, because the
license is just the GPL, there's nothing special about it.

> (*) A new authentication 'rlm_something' module is created by a
> party outside of  The module takes the supplied
> credentials and authenticates them in some fashion (e.g. via
> proxying to some other standalone AAA server).
> (*) The module is distributed as part of the aforementioned
> commercial AAA server distribution
> (*) In order to streamline deployment for the customers, FreeRadius
> (unmodified) is also distributed
> Questions:
> (*) Can this be legally done?

  There are restrictions, but yes.  The module MUST be licensed under
the GPL, as it is a derivative work of FreeRADIUS.  At that point, you
might as well submit the module to us for inclusion in the main release.

> (*) If the above rlm_ module depends on some external SDKs
> (unrelated to FreeRadius) and its source is contributed to
> FreeRadius, does the source to the SDK need to be contributed as
> well?

  Not necessarily.  For example, the FreeRADIUS modules depend on libc,
which is proprietary in many OS's.  If the libraries needed by a module
are normally part of the OS, then the source does not have to be
contributed back.  If, however, the libraries are not part of the OS,
but are part of the application you're selling along with FreeRADIUS,
then you have a choice:

  a) distribute the source to the libraries, too.  Likely under the GPL
  b) do not distribute FreeRADIUS or the module you're adding.

> (*) In general, what is the process for contributing an rlm_ module
> and incorporating it in the 'standard' FreeRadius distribution?  Send a patch.

> The bottom line is that I'd like to support FreeRadius in my
> commercial product and distribute FreeRadius as a convenience to
> customers.  What should I do to keep everyone happy?

  Money, bags and bags of money.

  :) Barring that, source code.

  Alan DeKok.
--       - The web site of the book - The blog

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