I started to skip but was interested in the ipfw configuration interface. I launched and was in the basic panel for Firewall after looking through other tabs. I do not have Firewall on in system prefs but I selected to enable logging and then to view current rules (apple default for off which allows all). I could not close the window that displayed active rules. The application froze. I never initiated any actions other than those noted. I forced quit the app. I tried to relaunch but it would not respond, only place the icon in the dock after bouncing without the 'active' arrow below. I finally had to force quit again and my persistence crashed the finder and I had to force reboot. I booted single user and journaling replayed but I forced fsck just in case. All seems to work now so no lasting damage.

Just suggest caution with my experience and the comments of others. It would be great if it worked without concern.