[nmglug] ssh attacks

I've been getting constant ssh attacks, like several per minute. Any suggestions?   I could change the port from 22, but I don't know if that will do much. There used to be some sort of sshd wrapper which could ban an IP after failed attempts.  I think it was deprecated.   The attack IP changes, but there often a few dozen attacks from the same IP. Again, some help...  but not much. I have password access disabled.  (You need to have a key to ssh in).  Anything else I should do? aaron