Sufentanil,
Yes you can run the server software on certain NAS devices, but the NAS device may be under powered if you want to use the optimal settings. For example, it's recommended to have the server stream the FLAC as PCM so the SBT doesn't have to do the work. For some, streaming native FLAC as opposed to PCM the difference was minor.
Dcowen1234, I tried using the SBT built in server to use the external HD and I don't recommend it. You'll just end up frustrated. That was the first thing I tried and ended up hating it. Scanning the library took too long and sometime it would crash. Once it crashed, it would have to scan again since it didn't run all the through the first time. I ended up reviving my old Dell Pentium 4 computer with XP and installed the Logictech Media Server and haven't run into any issues since them.