# block all ICMP packets. # block in proto icmp all # # allow in ICMP echos and echo-replies. # pass in on le1 proto icmp from any to any icmp-type echo pass in on le1 proto icmp from any to any icmp-type echorep # # block all ICMP destination unreachable packets which are port-unreachables # block in on le1 proto icmp from any to any icmp-type unreach code 3