Before purchasing my new DNS-321, I was flawlessly running FUPPES under Ubuntu 8.04. I've tried TwonkyVision and MediaTomb, but FUPPES (SVN-549) seemed to work the best. It's not the easiest to set up, but it set up the directories just the way I liked and was the only one out of the three that I could get to play FLAC files (with on the fly transcoding to WAV of course).
http://fuppes.ulrich-voelkel.de/
http://fuppes.ulrich-voelkel.de/wiki/index.php?title=Main_Page
With the DNS-321 in it's current form I've been finding that the DLNA server fails on occasion and clicking the refresh button has no effect. The only way to restore is to restart the 321. I've also found that Ubuntu after a day or two no longer sees the 321 Windows shares. Very strange and annoying to have to restart the box every other day. Has anyone hacked this device to add SSH like the 323?
http://wiki.dns323.info/