...
watch --no-title iptables -vL
Insert rule: Drop ICMP traffic:
iptables -I FORWARD -p ICMP -j DROP
Delete rule: Drop ICMP traffic:
iptables -D FORWARD -p ICMP -j DROP
...
watch --no-title iptables -vL
iptables -I FORWARD -p ICMP -j DROP
iptables -D FORWARD -p ICMP -j DROP