CentOS iptables防火墙使用

CentOS默认使用的是firewall作为防火墙，这里改为iptables防火墙

1、关闭firewall

#停止firewall
systemctl stop firewalld.service 
#禁止firewall开机启动
systemctl disable firewalld.service 

2、安装iptables防火墙

#安装
yum install iptables-services
#编辑防火墙配置文件 
vi /etc/sysconfig/iptables 
# 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
-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
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT
#最后重启防火墙使配置生效
systemctl restart iptables.service
#设置防火墙开机启动 
systemctl enable iptables.service