Yesterday my poor little home server was subjected to a two hour SSH dictionary attack. Root login via SSH is disabled, and user login is only via key exchange - I don't permit password based logins at all, so the spottly little Herbet didn't get in. However all the logging made a lot of noise, and my better half was not best pleased.
I've seen SSH dictionary attacks before, but normally they only have a few goes before giving up, this one was truly persistent. I'll have to investigate bandwith throttling and dynamic blacklisting options in future.