Can I make binaries available on a network server, but send sources only to people who order them?
If you make object code available on a network server, you have to provide the Corresponding Source on a network server as well. The easiest way to do this would be to publish them on the same server, but if you’d like, you can alternatively provide instructions for getting the source from another server, or even a version control system. No matter what you do, the source should be just as easy to access as the object code, though. This is all specified in section 6(d) of GPLv3. The sources you provide must correspond exactly to the binaries. In particular, you must make sure they are for the same version of the program—not an older version and not a newer version.
