vi /etc/sysconfig/iptables

-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT

/etc/init.d/iptables stop 
#start 开启 
#restart 重启

# 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

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）

[root@localhost ~]# /etc/init.d/iptables restart 
iptables：清除防火墙规则：                 [确定]
iptables：将链设置为政策 ACCEPT：filter          [确定]
iptables：正在卸载模块：                  [确定]
iptables：应用防火墙规则：Bad argument `–-state'
Error occurred at line: 11
Try `iptables-restore -h' or 'iptables-restore --help' for more information.
                              [失败]

[root@centos httpd]# /sbin/iptables -I INPUT -p tcp --dport 80 -j ACCEPT
[root@centos httpd]# /etc/rc.d/init.d/iptables save
[root@centos httpd]# /etc/init.d/iptables restart

[root@centos httpd]# /etc/init.d/iptables status