I'm in another state working, away from my home farm. I've got my hardware firewall at home set up to let ssh queries be routed to one machine, from that one I can check on the progress of the whole farm, kill and restart processes, reboot, whatever I need to do to tend the farm.

I browsed the auth.log file on my ssh server machine and found tons of attempts at access, with lists of usernames and root with them having no luck. I don't know much about security, other than don't use telnet and have secure passwords. Other than disable ssh access, is there anything I can do to stop this? I'm not too worried about them guessing my passwords, but isn't it eating up cpu cycles to answer constant access queries?