一、实验拓扑: Note: 路由条目穿越路由器才会增加跳数

二、命令部署: R3(config)#access-list 1 permit 4.0.0.0 0.0.0.255 //此处必须匹配4.0.0.0,因为默认汇总的就是这个网段,不然抓取不成功,可能是因为自动汇总的原因。

R3(config)#router rip R3(config-router)#offset-list 1 out 5 s3/0

三、验证: 1、未做偏移列表前,跳数为2 R1#show ip route R 34.0.0.0/8 [120/1] via 13.1.1.3, 00:00:07, Serial3/0 R 4.0.0.0/8 [120/2] via 13.1.1.3, 00:00:01, Serial3/0 [120/2] via 12.1.1.2, 00:00:01, FastEthernet0/0 R 24.0.0.0/8 [120/1] via 12.1.1.2, 00:00:26, FastEthernet0/0 12.0.0.0/24 is subnetted, 1 subnets 2、做偏移列表后: R1#show ip route rip R 34.0.0.0/8 [120/1] via 13.1.1.3, 00:00:19, Serial3/0 R 4.0.0.0/8 [120/2] via 12.1.1.2, 00:00:17, FastEthernet0/0 R 24.0.0.0/8 [120/1] via 12.1.1.2, 00:00:17, FastEthernet0/0 结果:R1只保留了4.4.4.4的最优路由条目,删除了通过13.1.1.3学习到的。 R3#show ip route rip 34.0.0.0/8 is variably subnetted, 2 subnets, 2 masks R 34.0.0.0/8 [120/3] via 13.1.1.1, 00:02:56, Serial3/0 R 4.0.0.0/8 [120/1] via 34.1.1.4, 00:00:15, FastEthernet1/0(因为是在出方向增加5,所以R3上4.4.4.4条目依然是1) R 24.0.0.0/8 [120/1] via 34.1.1.4, 00:00:15, FastEthernet1/0 R 12.0.0.0/8 [120/1] via 13.1.1.1, 00:00:08, Serial3/0