Big botnet attack kept hitting the server, locking me and some others out. As it's coming from hundreds of different sources (changing every couple of attempts) there's no real way to block it by IP, so I've moved SSH to a non-standard port (2222) which should hopefully keep them from finding/attacking for a bit and move on to the next target. It MAY move back in the future, but if you cannot connect to ssh/sftp, manually change the port to 2222 for now (instead of the default of just 22.)