第 2 层交换机和路由器对接互联网配置示例

配置路由器通过子接口终结VLAN，实现跨网段的三层转发。

# 配置终结子接口。

<Huawei> system-view
[Huawei] sysname Router
[Router] vlan batch 2 3   
[Router] interface gigabitethernet 0/0/1.1
[Router-GigabitEthernet0/0/1.1] dot1q termination vid 2   
[Router-GigabitEthernet0/0/1.1] ip address 192.168.1.1 24
[Router-GigabitEthernet0/0/1.1] arp broadcast enable//缺省状态下，AR路由器终结子接口的ARP广播功能在V200R003C01之前版本处于未使能状态，在V200R003C01及之后版本处于使能状态
[Router-GigabitEthernet0/0/1.1] quit
[Router] interface gigabitethernet 0/0/1.2
[Router-GigabitEthernet0/0/1.2] dot1q termination vid 3   
[Router-GigabitEthernet0/0/1.2] ip address 192.168.2.1 24
[Router-GigabitEthernet0/0/1.2] arp broadcast enable    
[Router-GigabitEthernet0/0/1.2] quit

# 配置DHCP功能，为内网用户分配IP地址和指定DNS服务器地址。

[Router] dhcp enable
[Router] interface gigabitethernet 0/0/1.1
[Router-GigabitEthernet0/0/1.1] dhcp select interface//DHCP使用接口地址池的方式为内网用户分配IP地址
[Router-GigabitEthernet0/0/1.1] dhcp server dns-list 114.114.114.114 223.5.5.5//配置的DNS-List 114.114.114.114是公用的DNS服务器地址，是不区分运营商的。在实际应用中，请根据运营商分配的DNS进行配置
[Router-GigabitEthernet0/0/1.1] quit
[Router] interface gigabitethernet 0/0/1.2
[Router-GigabitEthernet0/0/1.2] dhcp select interface   
[Router-GigabitEthernet0/0/1.2] dhcp server dns-list 114.114.114.114 223.5.5.5   
[Router-GigabitEthernet0/0/1.2] quit

# 配置公网接口的IP地址和静态路由。

[Router] interface gigabitethernet 0/0/2
[Router-GigabitEthernet0/0/2] ip address 1.1.1.2 255.255.255.0//配置连接公网的接口GE0/0/2的IP地址1.1.1.2
[Router-GigabitEthernet0/0/2] quit
[Router] ip route-static 0.0.0.0 0.0.0.0 1.1.1.1//配置静态缺省路由的下一跳指向公网提供的IP地址1.1.1.1

# 配置NAT功能，使内网用户可以访问外网。

[Router] acl number 2001
[Router-acl-basic-2001] rule 5 permit source 192.168.0.0 0.0.255.255//NAT转换只对源IP地址是192.168.0.0/16网段的生效，并在接口GE0/0/2的出方向进行转换
[Router-acl-basic-2001] quit
[Router] interface gigabitethernet 0/0/2
[Router-GigabitEthernet0/0/2] nat outbound 2001
[Router-GigabitEthernet0/0/2] quit