vi /etc/sysconfig/iptables
在打开的文件中（在配置22端口的下一行），添加 -A INPUT -m state --state NEW -m tcp -p tcp --dport 3306 -j ACCEPT（允许3306端口通过防火墙）
######################################
# 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 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
原文：http://www.cnblogs.com/xbq8080/p/6646813.html