logwatcher in action #tags grok Kenya, one of my machines, sends me security reports daily (Thanks FreeBSD!).
kenya.csh.rit.edu login failures:
Sep 15 11:15:24 kenya sshd[32882]: Failed password for illegal user a from 218.44.208.162 port 2946 ssh2
Sep 15 11:58:55 kenya sshd[32986]: Failed password for illegal user root from 212.0.132.27 port 40961 ssh2
Sep 15 21:59:03 kenya sshd[34537]: Failed password for illegal user test from 218.44.208.162 port 3614 ssh2
Notice how there was only one root-user attempt and only 2 illegal-user attempts? My logwatcher is configured to instantly block any root login attempts aswell as anyone who tries to login with an invalid user more than once. Keeps the brute-force attempts out of my logs.

Doing this is certainly not a catch-all solution by any means, but definately it keeps my security logs clear of idiots.

Anyone who gets blocked by being naughty on ssh goes into the whores table in pf. That table has been growing steadily for a few weeks now...

kenya(~) [1000] % sudo pfctl -t whores -T show | wc -l
     129
Logwatcher most definately isn't just for security, but the only thing I use it for is to watch auth.log for brute-force bot activity. I'm hoping to have some spare time to spend on developing more neat features into logwatcher as time progresses. Right now, though, it's pretty slick. If you want more information about logwatcher, feel free to visit the logwatcher project page or find me online (aim or email) and bug me with questions or feature requests.