Spent about an hour trying to work out why the aforementioned NAS box was totally failing. The ftp server seemed to be working, the machine seemed to be identifying itself.
Turned out to be the firewall. Windows can cope without a call-back it seems. It looks rather like this was also the cause of poor performance on small files. I’ve managed to get my network card up to 30% utilisation; saturday it was rarely more than 2%.
Originally published on my old blog site.