Time Machine does not work over the Internet

This might not come as a surprise to you, but I’ve been experimenting just to see if Time Machine might be able to backup my dad’s (Gunnar’s) MacBook and my girlfriend’s mom’s (Mia’s) MacBook over the Internet to my 10.5 Server. It isn’t. I started the experiment in December. Mia’s backup had succeeded three times, all on December 17, for a total of 17GB. After that, Time Machine had shown progress bars and everything, but only completed four partial backups for a total of 40MB. Fourty megabytes in two months, all of it trying to backup /Applications. Gunnar’s backup never completed even once in the same period. The .sparseimage was four megabytes, and the only transferred file seemed to be the alias for “User guides and documentation” that appears in the volume root of some installations. He had also reported that Time Machine frequently showed progress bars. I really expected it to work, since, you know, it’s just a TCP link and the underlyi...