Centos7 closes firewall and installs iptables

By default, the firewall is violently closed:
sudo iptables -F
The following is the correct way: refer to http://www.open-open.com/lib/view/open1411818940031.html
to uninstall the default firewall and install iptables

to close the firewall:

sudo systemctl stop firewalld.service #停止firewall
sudo systemctl disable firewalld.service #Prohibit firewall from starting

Install iptables firewall

sudo yum install iptables-services #installation
sudo vim /etc/sysconfig/iptables #Edit firewall configuration file

Modifications are as follows

# Firewall configuration written by system-config-firewall
# Manual customization of this file is not recommended.
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
# Open port 80,3306
[color=green]-A INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 3306 -j ACCEPT[/color]
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT

:wq #Save and exit

sudo systemctl restart iptables.service #Finally restart the firewall to make the configuration take effect
sudo systemctl enable iptables.service #Set the firewall to start at boot

Just reboot.