Linux配置防火墙，开启80端口、3306端口

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

添加好之后防火墙规则如下所示：

######################################  # 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