实验步骤：

第一步：地址规划拓扑设计，配置IP地址

R1配置：

<Huawei>system-view 
[Huawei]sy R1
[R1]int g 0/0/1
[R1-GigabitEthernet0/0/1]ip address 192.168.1.1 24
[R1-GigabitEthernet0/0/1]int g 0/0/0
[R1-GigabitEthernet0/0/0]ip add 12.1.1.1 24
[R1-GigabitEthernet0/0/0]q

R2配置：

<Huawei>SY
[Huawei]SY R2
[R2]int g 0/0/0
[R2-GigabitEthernet0/0/0]ip add 12.1.1.2 24
[R2-GigabitEthernet0/0/0]int g 0/0/1
[R2-GigabitEthernet0/0/1]ip add 23.1.1.1 24
[R2-GigabitEthernet0/0/1]q

R3配置：

<R3>sy
Enter system view, return user view with Ctrl+Z.
[R3]sy R3
[R3]int g 0/0/0
[R3-GigabitEthernet0/0/0]ip add 23.1.1.2 24
[R3-GigabitEthernet0/0/0]int g 0/0/1
[R3-GigabitEthernet0/0/1]ip add 32.1.1.1 24

R4配置：

<R4>sy
[R4]sy R4
[R4]int g 0/0/0
[R4-GigabitEthernet0/0/0]ip add 32.1.1.2 24
[R4-GigabitEthernet0/0/0]int g 0/0/1
[R4-GigabitEthernet0/0/1]ip add 192.168.1.1 24

第二步：公网路由配置，因上课时使用过OSPF，因此此时使用RIP

R2配置:

[R2]rip 1
[R2-rip-1]version 2
[R2-rip-1]network 12.0.0.0
[R2-rip-1]network  23.0.0.0

R3配置：

[R3]rip 1 
[R3-rip-1]version 2	
[R3-rip-1]network 23.0.0.0
[R3-rip-1]network 32.0.0.0

第三步：配置网内缺省路由

R1配置：

[R1]ip route-static 0.0.0.0 0 12.1.1.2

R4配置：

[R4]ip route-static 0.0.0.0 0 32.1.1.1

第四步：配置NAT

R1配置：

[R1]acl 2000
[R1-acl-basic-2000]rule 1 permit source any 
[R1-acl-basic-2000]q
[R1]int g 0/0/0
[R1-GigabitEthernet0/0/0]nat outbound 2000

R4配置：

[R4]acl 2000
[R4-acl-basic-2000]rule 1 permit source any 
[R4-acl-basic-2000]q
[R4]int g 0/0/0
[R4-GigabitEthernet0/0/0]nat outbound 2000

第五步：配置GRE

R1配置：

[R1]int  Tunnel 0/0/0
[R1-Tunnel0/0/0]tunnel-protocol gre 
[R1-Tunnel0/0/0]ip add 10.1.1.1 24
[R1-Tunnel0/0/0]source 12.1.1.1
[R1-Tunnel0/0/0]destination  32.1.1.2

[R1]int Tunnel 0/0/0 创建隧道口
[R1-Tunnel0/0/0]tunnel-protocol gre 定义封装方式为gre
[R1-Tunnel0/0/0]ip add 10.1.1.1 24 配置隧道IP地址
[R1-Tunnel0/0/0]source 12.1.1.1 定义封装源
[R1-Tunnel0/0/0]destination 32.1.1.2 定义封装内容目标

R4配置：

[R4]int Tunnel 0/0/0
[R4-Tunnel0/0/0]tunnel-protocol gre 
[R4-Tunnel0/0/0]ip add 10.1.1.2 24
[R4-Tunnel0/0/0]source 32.1.1.2
[R4-Tunnel0/0/0]destination  12.1.1.1

第六步：书写静态路由指向隧道

[R1]ip route-static 192.168.1.0 24 Tunnel 0/0/0
[R4]ip route-static 192.168.2.0 24 Tunnel 0/0/0

第七步：测试

PC>ping 192.168.2.2

Ping 192.168.2.2: 32 data bytes, Press Ctrl_C to break
Request timeout!
From 192.168.2.2: bytes=32 seq=2 ttl=126 time=47 ms
From 192.168.2.2: bytes=32 seq=3 ttl=126 time=31 ms
From 192.168.2.2: bytes=32 seq=4 ttl=126 time=31 ms
From 192.168.2.2: bytes=32 seq=5 ttl=126 time=47 ms

--- 192.168.2.2 ping statistics ---
  5 packet(s) transmitted
  4 packet(s) received
  20.00% packet loss
  round-trip min/avg/max = 0/39/47 ms