R1(config-router)#no auto-summary

（2）配置R2

R2(config)#router eigrp 100

R2(config-router)#net 12.12.12.0 0.0.0.255

R2(config-router)#net 23.23.23.0 0.0.0.255

R2(config-router)#net 172.16.1.0 0.0.0.255

R2(config-router)#no auto-summary

（3）配置R3

R3(config)#router eigrp 100

R3(config-router)#net 23.23.23.0 0.0.0.255

R3(config-router)#net 192.168.1.0 0.0.0.255

R3(config-router)#no auto-summary

3． 认证

R1#show ip route

Gateway of last resort is not set

10.0.0.0/24 is subnetted, 1 subnets

C 10.1.1.0 is directly connected, FastEthernet0/0

12.0.0.0/24 is subnetted, 1 subnets

C 12.12.12.0 is directly connected, Serial1/0

23.0.0.0/24 is subnetted, 1 subnets

D 23.23.23.0 [90/21024000] via 12.12.12.2, 00:47:41, Serial1/0

172.16.0.0/24 is subnetted, 1 subnets

D 172.16.1.0 [90/20514560] via 12.12.12.2, 00:47:41, Serial1/0

D 192.168.1.0/24 [90/21026560] via 12.12.12.2, 00:47:41, Serial1/0

R2#show ip route

Gateway of last resort is not set

10.0.0.0/24 is subnetted, 1 subnets

D 10.1.1.0 [90/20514560] via 12.12.12.1, 00:49:02, Serial1/0

12.0.0.0/24 is subnetted, 1 subnets

C 12.12.12.0 is directly connected, Serial1/0

23.0.0.0/24 is subnetted, 1 subnets

C 23.23.23.0 is directly connected, Serial1/1

172.16.0.0/24 is subnetted, 1 subnets

C 172.16.1.0 is directly connected, FastEthernet0/0

D 192.168.1.0/24 [90/20514560] via 23.23.23.3, 00:49:07, Serial1/1