RIPv2在企業內網的應用

R1、R2、R3模擬企業內網跑RIPv2路由協議，R3是企業網關，實現全網互通，內網通過NAT轉換訪問Internet，目標爲4.4.4.4/24

 

R1
en
conf t
line con 0
no exec-t
exit
host R1
int f0/0
no sh
ip add 192.168.12.1 255.255.255.0
exit
router rip
ver 2
no au
net 192.168.12.0

===================R2============================
en
conf t
line con 0
no exec-t
exit
host R2
int f0/0
no sh
ip add 192.168.12.2 255.255.255.0
int f1/0
no sh
ip add 192.168.23.2 255.255.255.0
exit
router rip
ver 2
no au
net 192.168.12.0
net 192.168.23.0
end

================R3=========================

en
conf t
line con 0
no exec-t
exit
host R3
int f0/0
no sh
ip add 192.168.23.3 255.255.255.0
int f1/0
no sh
ip add 34.34.34.3 255.255.255.0
int lo 0
ip add 3.3.3.3 255.0.0.0 
exit
router rip
ver 2
no au
net 192.168.23.0
end

R3(config)#ip default-network 3.0.0.0 向內網下發默認路由
R3(config)#ip route 0.0.0.0 0.0.0.0 34.34.34.4

NAT配置
R3(config)#access-list 1 permit 192.168.0.0 0.0.255.255
R3(config)#ip nat inside source list 1 interface FastEthernet1/0 overload      
R3(config)#interface FastEthernet0/0
R3(config-if)#ip nat inside
R3(config)#interface FastEthernet1/0
R3(config-if)#ip nat outside

===================R4===============================

en
conf t
line con 0
no exec-t
exit
host R4
int f0/0
no sh
ip add 34.34.34.4 255.255.255.0
int lo0
no sh
ip add 4.4.4.4 255.255.255.0

 

實驗調試

向內網下發默認路由後，會產生一條指向下一跳的默認路由

R1#sh ip route
Gateway of last resort is 192.168.12.2 to network 0.0.0.0

C    192.168.12.0/24 is directly connected, FastEthernet0/0
R    192.168.23.0/24 [120/1] via 192.168.12.2, 00:00:01, FastEthernet0/0
R*   0.0.0.0/0 [120/2] via 192.168.12.2, 00:00:01, FastEthernet0/0

 

R2#sh ip route
Gateway of last resort is 192.168.23.3 to network 0.0.0.0

C    192.168.12.0/24 is directly connected, FastEthernet0/0
C    192.168.23.0/24 is directly connected, FastEthernet1/0
R*   0.0.0.0/0 [120/1] via 192.168.23.3, 00:00:23, FastEthernet1/0

R3#sh ip route
Gateway of last resort is 34.34.34.4 to network 0.0.0.0

     34.0.0.0/24 is subnetted, 1 subnets
C       34.34.34.0 is directly connected, FastEthernet1/0
R    192.168.12.0/24 [120/1] via 192.168.23.2, 00:00:17, FastEthernet0/0
C*   3.0.0.0/8 is directly connected, Loopback0
C    192.168.23.0/24 is directly connected, FastEthernet0/0
S*   0.0.0.0/0 [1/0] via 34.34.34.4

NAT調試

R3#debug ip nat
IP NAT debugging is on
R3#
*Mar  1 00:35:16.295: NAT*: s=192.168.12.1->34.34.34.3, d=4.4.4.4 [25]
*Mar  1 00:35:16.391: NAT*: s=4.4.4.4, d=34.34.34.3->192.168.12.1 [25]
*Mar  1 00:35:16.515: NAT*: s=192.168.12.1->34.34.34.3, d=4.4.4.4 [26]
*Mar  1 00:35:16.563: NAT*: s=4.4.4.4, d=34.34.34.3->192.168.12.1 [26]
*Mar  1 00:35:16.631: NAT*: s=192.168.12.1->34.34.34.3, d=4.4.4.4 [27]
*Mar  1 00:35:16.671: NAT*: s=4.4.4.4, d=34.34.34.3->192.168.12.1 [27]
*Mar  1 00:35:16.763: NAT*: s=192.168.12.1->34.34.34.3, d=4.4.4.4 [28]
*Mar  1 00:35:16.795: NAT*: s=4.4.4.4, d=34.34.34.3->192.168.12.1 [28]
*Mar  1 00:35:16.907: NAT*: s=192.168.12.1->34.34.34.3, d=4.4.4.4 [29]
R3#
*Mar  1 00:35:16.999: NAT*: s=4.4.4.4, d=34.34.34.3->192.168.12.1 [29]

 

測試ping

R1#ping 4.4.4.4

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 4.4.4.4, timeout is 2 seconds:
!!!!!

R1#traceroute 4.4.4.4

Type escape sequence to abort.
Tracing the route to 4.4.4.4

  1 192.168.12.2 128 msec 96 msec 60 msec
  2 192.168.23.3 128 msec 76 msec 140 msec
  3 34.34.34.4 252 msec *  232 msec

 

注意事項：

• 向rip網絡中注入默認路由先ip default-network，後寫指向外網的默認路由，宣告ip default-network 必須是有類
• 一般企業分配的公有IP是無類的，所以必須在環回口上宣告一個有類ip地址，例如本文的R3上3.3.3.3/8