Linux Route :eth0 172.16.0.1
eth1 60.59.58.1
Intranet windows 172.16.0.100 ,172.16.0.101 netmask 255.255.255.0 gateway 172.16.0.1
Extranet windows 60.59.58.100 ,60.59.58.200 netmask 255.255.255.0 gateway 60.59.58.1
Intranet 机器可以访问所有Externet机器，Extranet 只有60.59.58.100能访问Intranet 172.16.0.100 的80和8080端口。
Linux配置如下：
双网卡 eth0 ：172.16.0.1、eth1：60.59.58.1
#echo “1” > /proc/sys/net/ipv4/ip_forward
#iptables –F
#iptables –X
#iptables –P FORWARD DROP
#iptables –A FORWARD –m state –state ESTABLISHED,RELATED –j ACCEPT
#iptables –A FORWARD –s 172.16.0.0/24 –j ACCEPT
#iptables –A FORWARD –s 60.59.58.100 –d 172.16.0.100 –p tcp –dport 80 –j ACCEPT
#iptables –A FORWARD –s 60.59.58.100 –d 172.16.0.100 –p tcp –dport 8080 –j ACCEPT
#iptables-save >/etc/sysconfig/iptables
