Script automatically downloads ip list to /tmp, and installs in ipfw table 1.

create a rule like 
ipfw -q add 940 deny ip from 'table(1)' to an

add to cron a rule like this: adjust times as needed. list updates every few hours typically.
0       1,5,9,13,17,21  *       *       root    /usr/local/bin/firehol.sh
