centos7关闭防火墙，使用iptables防火墙

环境
centos7

借鉴了http://blog.163.com/yang_shunnian/blog/static/7234452015225111522575/

1.禁用Firewalld

#停止firewall
systemctl stop firewalld.service
#禁止firewall开机启动
systemctl disable firewalld.service
#查看默认防火墙状态（关闭后显示notrunning，开启后显示running）
firewall-cmd --state

2.iptables防火墙

#安装iptables
yum install iptables-services
#开机自启动
systemctl enable iptables
#启动iptables
systemctl start iptables

3.iptables相关配置
配置在【/etc/sysconfig/iptables】
下面为配置示例

# 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 21 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 25 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 53 -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 -m state --state NEW -m tcp -p tcp --dport 5666 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT

在CentOS/RHEL 7上开启端口

#永久打开一个新端口（如TCP/80）如果不使用“--permanent”标记，把么防火墙规则在重启后会失效
firewall-cmd --zone=public --add-port=80/tcp --permanent
#重新加载配置
firewall-cmd --reload
#查看已经开放的端口：
firewall-cmd --list-ports
#停止firewall
systemctl stop firewalld.service
#禁止firewall开机启动
systemctl disable firewalld.service

在CentOS/RHEL 6上开启端口

iptables -I INPUT -p tcp -m tcp --dport 80 -j ACCEPT
#保存
service iptables save