owner of the Medion Nas. I hope this is the right place to ask (NSA210).
Well, there *are* some similarities. The '210 runs an Oxnas 810 processor, while the Medion runs it's successor, the Oxnas 820.
But of course this is actually an FFP question, which has nothing to do with the actual hardware.
You should move your script from /ffp/start/ to, for instance, /ffp/bin/, as all executable scripts in /ffp/start are executed on boot, and your script needs some special parameters.
The reason your server stops if you close putty is that it has open output pipes to that console. Closing the console means closing the program running within. You'll have to redirect the output, and run it in background.
Create a script in /ffp/start/, having an .sh extension and the executable flag set, which does:
if [ "$1" = "start" ] ; then
/ffp/bin/ps3netsr.sh /i-data/W1E50D6L/PS3 38008 192.168.178.* >/dev/null 2>&1 &
The > redirects the output to the universal thrashbin, /dev/null, 2>&1 redirects 'stderr' to 'stdout', and the closing & puts the script in background.