1、设置防火墙不拦截ICMP报文

• 防火墙放行ICMP

[root@localhost ~]# firewall-cmd --add-protocol=icmp
success
[root@localhost ~]# firewall-cmd --reload 
success
[root@localhost ~]# firewall-cmd --list-all
public (active)
  target: default
  icmp-block-inversion: no
  interfaces: ens160
  sources: 
  services: cockpit dhcpv6-client ssh
  ports: 
  protocols: icmp
  masquerade: no
  forward-ports: 
  source-ports: 
  icmp-blocks: 
  rich rules: 

• 防火墙关闭

[root@localhost ~]# systemctl stop firewalld

2、修改Linux主机不响应ICMP报文

[root@localhost ~]# cat /proc/sys/net/ipv4/icmp_echo_ignore_all 
0
[root@localhost ~]# echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all

• 0：响应；
• 1：不响应；

注意：此文件不可通过vi/vim进行修改，报错如下：

"/proc/sys/net/ipv4/icmp_echo_ignore_all"
"/proc/sys/net/ipv4/icmp_echo_ignore_all" E667: Fsync failed
Press ENTER or type command to continue

3、效果展示