"Anyone who runs their own Linux server knows the annoyance of
looking through the log files to see automated SSH brute force
attacks trying to find a login to the machine. In the past, I've
avoided this problem simply by running sshd on a non-traditional
port, which makes all the automated scripts that attack port 22
fail.
I recently had to move sshd back to port 22, and I quickly tired
of seeing 5k failed login attempts every day.
A little bit of Googling, and my firewall has been updated in a
way that has eliminated almost all of those failed logins.