iptables -t {mangle|filter|nat} -LYou can also add the --line-number option to print rules numbers
iptables -t {mangle|filter|nat} -D CHAIN RULE_NUMBERNotice that to get the row number you can ues the first command in this gist
iptables -t filter -I INPUT -p icmp --icmp-type echo-request -j REJECTNotice that REJECT returns error, you can use DROP to totally not respond on the request
iptables -t filter -I OUTPUT -p icmp --icmp-type echo-request -j REJECTiptables -t mangle -I POSTROUTING -j TTL --ttl-set 100
Good work my bro