三层交换机有几个VLAN都要上外网，交换机和路由器相连,可以访问外网。

1）开启VLAN子接口，配置VLAN网关，这样就能完成VLAN之间的通讯了。

三层交换机，开启VLAN子接口，配置VLAN网关，详见
http://www.itale.cn/archives/2016/1/20160108085907.html

2）三层交换机中与路由器连接的接口g0/1配置成三层接口模式no switchport，配置IP地址与路由器同网段相连。

Switch>enable
Switch#configure terminal
Switch(config)#interface GigabitEthernet0/1
Switch(config-if)#no switchport
	
Switch(config-if)#ip add 101.7.200.1 255.255.255.0
Switch(config-if)#exit

3）配置缺省路由，三层交换机需要配置去往外网的路由，路由器需要同时配置去往外网的缺省路由和去往内网的静态路由。
三层交换机路由：

Switch>enable
Switch#configure terminal
Switch(config)#ip route 101.7.180.0 255.255.255.0 101.7.200.2
Switch(config)#


配置路由器0的接口f0/0，f0/1地址：

Router#configure terminal

Router(config)#interface FastEthernet0/0

Router(config-if)#ip address 101.7.200.2 255.255.255.0
Router(config-if)#exit

Router(config)#interface FastEthernet0/1
Router(config-if)#ip address 219.226.127.224 255.255.255.0
Router(config-if)#exit

配置路由器0的路由：
Router(config)#
Router(config)#ip route 101.7.180.0 255.255.255.0 219.226.127.225
Router(config)#
Router(config)#ip route 101.7.0.0 255.255.0.0 101.7.200.1

4）添加http服务器，两边测试。
http://101.7.180.4
http://101.7.161.5

5）Router0 route

Router>show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
       i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
       * - candidate default, U - per-user static route, o - ODR
       P - periodic downloaded static route

Gateway of last resort is not set

        101.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
S       101.7.0.0/16 [1/0] via 101.7.200.1
S       101.7.180.0/24 [1/0] via 219.226.127.225
C       101.7.200.0/24 is directly connected, FastEthernet0/0
C       219.226.127.0/24 is directly connected, FastEthernet0/1
Router>

6）Router1 route
Router>show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
       i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
       * - candidate default, U - per-user static route, o - ODR
       P - periodic downloaded static route

Gateway of last resort is not set

     101.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
S       101.7.0.0/16 [1/0] via 219.226.127.224
C       101.7.180.0/24 is directly connected, FastEthernet0/1
C    219.226.127.0/24 is directly connected, FastEthernet0/0
Router>