Qmail is not Open Source (page 40)
More...Reported on: 2005-12-13
In chapter 2. The Debian Project on page 40:
In the end of section 2.2.2, I cite Qmail as an example of non-free open source software. Here, I have made the common mistake of equating availability of source with "open-source-ness". Qmail is non-free, and not Open Source by the Open Source Definition, although its sources are available.
Discussion
Qmail does not allow for free redistribution of modified binaries. The Open Source Definition is based on the Debian Free Software Guidelines (indeed it is a modified version of the DFSG, penned by the same author), so the Qmail licence does not conform to the OSD and is not OSI-certified. It does not appear on the list of valid licences.
If the Qmail licence were Open Source, then so would Microsoft's "Shared Source" or the Sun Community Licence be Open Source. To avoid this particular mistake, the Open Source Initiative has registered the term "Open-Source" as a certification mark (OSI also tried to register a proper trademark, but without success).
This certification mark and the unambiguity of the term was the primary reason for forming the OSI. I failed to mention or acknowledge the existance of this certification mark and treated the term "Open Source" as though it meant nothing more than "source is available".