Looking at my auth.log on an internet accessible server. I notice that there has been 3071 unsuccesful login attempts since last the logs rotated.

cat /var/log/auth.log | grep invalid | grep ssh  | wc
3071   49136  327541

# does any one know how to match two arguments using AND logic for grep?
# let me know if you do.

Hmm I had better do something about it:

Good general guide on Securing SSH
http://wiki.centos.org/HowTos/Network/SecuringSSH

How to get a Debian / Ubuntu box to keep the iptables configuration across reboots
http://www.debian-administration.org/articles/445