Almost every day I get a:
<38>May 4 03:47:15 sshd[28281]: Invalid user ftpuser from 75.180.23.60
<35>May 4 03:47:15 sshd[28281]: error: Could not get shadow information for NOUSER
<38>May 4 03:47:15 sshd[28281]: Failed password for invalid user ftpuser from 75.180.23.60 port 1082 ssh2

in my messages log.. Different asshole each time..

Here is a couple more:

<38>May 4 01:41:05 sshd[28269]: Did not receive identification string from 71.4.52.81
<38>May 4 01:41:39 sshd[28270]: Failed password for invalid user admin from 71.4.52.81 port 60181 ssh2
<38>May 3 12:53:55 sshd[28097]: Invalid user admins from 193.216.2.238

And if i Google the last ip, I get a couple indications that I'm not alone..

Brute force assholes... But according to http://www.linuxsecurity.com/content/view/119238/151/ it might just be a zombie-machine.. doh..

Now I've installed denyhosts package, wonder if it works..