1.编辑防火墙过滤设置
vi /etc/sysconfig/iptables
-A INPUT -m state –state NEW -m tcp -p tcp –dport 80 -j ACCEPT(允许80端口通过防火墙)
-A INPUT -m state –state NEW -m tcp -p tcp –dport 3306 -j ACCEPT(允许3306端口通过防火墙)
特别提示：很多网友把这两条规则添加到防火墙配置的最后一行，导致防火墙启动失败，正确的应该是添加到默认的22端口这条规则的下面
# 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
/etc/init.d/iptables restart
#最后重启防火墙使配置生效
重启防火墙
方法一:
service iptables restart
方法二
/etc/init.d/iptables restart
#查看当前连接端口的状态
lsof -i:3306
#查看防火墙状态
chkconfig iptables --list
service iptables status
iptables 0:关闭 1:关闭 2:启用 3:启用 4:启用 5:启用 6:关闭
linux有六个运行级别，0(关机)，1单用户，2多用户(无NFS)，3完全多用户，4(未使用)，5图形界面X11，6重启