Now, at the IETF-60 meeting, it was pointed out that qmail has a
quirky license. (Many/most people do not consider qmail to be Open
Source Software because of its license.) Basically, only the
original author can modify qmail, all other changes must be
distributed separately and applied as patches. As the original author
hasn't updated qmail for years, almost all qmail users take the
original source and apply one or more sets of "patches" in order to
create an MTA (mail server) which they can use.
Would a qmail patch author qualify as a "licensed implementation" and
thus someone who takes qmail and creates a derivative work of it by
apply the patch qualify as an "end user"?
If not, wouldn't this mean that users of qmail that want to support
SenderID (which we hope will be all of them) need to get a license
from Microsoft?
Or an alternative MTA :-)
Section 1.2 gives the definition of a "Licensed Implementation",
which, in the second of the two (ii) clauses, requires you to have
branded trademark. Do any patches have trademarks?
Apache began as a set of patches to the NCSA web server so it would
appear to be the case.
There are several cases where a software product has been created
as a configuration of another system, why not distribute the
configuration in patch form?
If I had to patch Qmail the way I would do it is as follows:
1) First write a patch that allows the server to load in sharable
object libraries as part of the startup procedure.
2) Write a second patch that causes the sharable object libraries
to be called during the appropriate processing stages (c.f. the
schemes used to load plugins into Netscape servers, IIS etc.)
3) Write the Sender-ID plug in as a separate stand alone sharable
object library that is initialized and called from QMAIL.
4) Get a Sender-ID license for the plug in separately from the
patches required to make it work.
Incidentally, I would do it that way regardless of the license
restrictions. If the code is written in the right way you can
shed and reinstall libraries without having to shut down mail
processing.