CentOS7默認的防火牆不是iptables,而是firewall.
由於習慣了用iptables作為防火牆，所以在安裝好centos7系統后，會將默認的firewall關閉，並另安裝iptables進行防火牆規則設定
下面介紹centos7關閉firewall安裝iptables，並且開啟80端口、3306端口的操作記錄：
[root@localhost ~]# cat /etc/redhat-release
CentOS Linux release 7.2.1511 (Core)
1、關閉firewall：
[root@localhost ~]# systemctl stop firewalld.service //停止firewall [root@localhost ~]# systemctl disable firewalld.service //禁止firewall開機啟動
2、安裝iptables防火牆
[root@localhost ~]# yum install iptables-services //安裝 [root@localhost ~]# vim /etc/sysconfig/iptables //編輯防火牆配置文件 # 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 [root@localhost ~]# systemctl restart iptables.service //最后重啟防火牆使配置生效 [root@localhost ~]# systemctl enable iptables.service //設置防火牆開機啟動 [root@localhost ~]# iptables -L //查看防火牆規則,默認的是－t filter，如果是nat表查看，即iptables －t nat -L
二、關閉SELINUX
[root@localhost ~]# vim /etc/selinux/config #SELINUX=enforcing //注釋掉 #SELINUXTYPE=targeted //注釋掉 SELINUX=disabled //增加 [root@localhost ~]# setenforce 0 //使配置立即生效