vim /etc/sysconfig/iptables
-A INPUT -p icmp -m icmp --icmp-type time-exceeded -j DROP
-A OUTPUT -p icmp -m icmp --icmp-type time-exceeded -j DROP

重启iptables服务：
systemctl restart iptables

检查新添加的规则是否有效，检查命令：
iptables -L -n