This works for small servers very well. For larger targets it only delays the attacks. Moving
the ssh to port 9223 or some such on machine www.bigsite.com stopped the main robots but after
a bit a new set of people showed up with bots after they had done a nmap. I am guessing they
saw it and then told their bot-herd to go after the hi-port. However the small home machine I
have, has never had a scan go high.