How do I just block an IP from accessing anything on a machine using IPFW on FreeBSD? I've tried several commands and none seem to do it - they either lock the box down completely or dont block anything.
If you don't have IPFW compiled in your kernel, you should load the module and add allow all rule as deny all is the default and it will lock you out.
IPFW module load: kldload ipfw && ipfw -q add 65534 allow ip from any to any
List rules: ipfw list
Deny IP: ipfw add <rule> deny ip from <IP> to any in
("in" parameter is optional, while <rule> can be 1-65533)