打开配置文件 
[root@localhost ~]# vi /etc/sysconfig/iptables
正确的配置文件 
# 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 -j REJECT –reject-with icmp-host-prohibited 
-A FORWARD -j REJECT –reject-with icmp-host-prohibited 
COMMIT
-A INPUT -m state –state NEW -m tcp -p tcp –dport * -j ACCEPT
注意点：新开放的端口一定要在端口22后面
重启防火墙使配置生效 
[root@localhost ~]# /etc/init.d/iptables restart
其它
查看开放端口 
[root@localhost ~]# /etc/init.d/iptables status
关闭防火墙 
[root@localhost ~]# /etc/init.d/iptables stop