rule FORWARD -p IPv4 --ip-protocol udp --ip-destination-port 67 -j OUT_ONLY
rule OUTPUT -p IPv4 --ip-protocol udp --ip-destination-port 67 -j OUT_ONLY

rule FORWARD -p IPv4 --ip-protocol udp --ip-destination-port 68 -j IN_ONLY
rule INPUT -p IPv4 --ip-protocol udp --ip-destination-port 68 -j IN_ONLY