-P INPUT DROP -P FORWARD DROP -P OUTPUT DROP -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT -A INPUT -i lo -j ACCEPT -A INPUT -p icmp -j ACCEPT -A INPUT -p tcp -m tcp --dport 22 -j ACCEPT -A INPUT -d 224.0.0.251/32 -p udp -m udp --dport 5353 -j ACCEPT -A OUTPUT -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT -A OUTPUT -o lo -j ACCEPT