目的：希望实现每个客户之间不通讯，但同时利用一个网关连接到INTERNET.
3550-emi 配置
interface FastEthernet0/1
switchport access vlan 1
switchport protected
no ip address
!
interface FastEthernet0/2
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/3
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/4
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/5
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/6
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/7
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/8
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/9
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/10
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/11
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/12
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/13
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/14
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/15
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/16
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/17
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/18
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/19
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/20
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/21
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/22
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/23
switchport access vlan 2
switchport protected
no ip address
!
interface FastEthernet0/24
switchport access vlan 2
switchport protected
no ip address
!
interface GigabitEthernet0/1
switchport trunk encapsulation dot1q
no ip address
!
interface GigabitEthernet0/2
no ip address
!
interface Vlan1
ip address 172.16.1.1 255.255.0.0
shutdown
!
interface Vlan2
ip address 10.1.1.1 255.255.0.0
ip access-group 1 in
!
interface Vlan3
ip address 10.2.1.1 255.255.0.0
ip access-group 2 in
!
ip route 0.0.0.0 0.0.0.0 Vlan1
!
ip classless
ip http server
2950G配置：
interface FastEthernet0/1
switchport access vlan 3
no ip address
!
interface FastEthernet0/2
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/3
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/4
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/5
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/6
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/7
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/8
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/9
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/10
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/11
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/12
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/13
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/14
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/15
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/16
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/17
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/18
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/19
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/20
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/21
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/22
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/23
switchport access vlan 3
switchport protected
no ip address
!
interface FastEthernet0/24
switchport access vlan 3
switchport protected
no ip address
!
interface GigabitEthernet0/1
switchport trunk encapsulation dot1q
no ip address
!
interface GigabitEthernet0/2
no ip address
!
interface Vlan1
no ip address
FW:领导，这个例子不能称之为PVLAN吧。
PVLAN的简介如下：PVLAN技术
现在有了一种新的VLAN机制，服务器同在一个子网中，但服务器只能与自己的缺省网关通信。这一新的VLAN特性就是专用VLAN(private VLAN, pVLAN)。专用VLAN是第2层的机制，在同一个2层域中有两类不同安全级别的访问端口。与服务器连接的端口称作专用端口(Private port)，一个专用端口限定在第2层，它只能发送流量到混杂端口，也只能检测从混杂端口来的流量。混杂端口(Promioscuous port)没有专用端口的限定，它与路由器或第3层交换机接口相连。简单地说，在一个专用VLAN内，专用端口收到的流量只能发往混杂端口，混杂端口收到的流量可以发往所有端口(混杂端口和专用端口)。
专 用 VLAN 的 应 用 对于保证城域接入网络的数据通讯的安全性 是 非 常 有 效的用户只需与自己的缺省网关连接，一个专用VLAN不需要多个VLAN 和IP 子 网 就 提 供 了 具备第二层数据通讯安全性的连接，所有的用户都接入专用 VLAN，从而实现了所有用户与缺省网关的连接，而与专用VLAN内的其他用户没
