递归表查询法配置静态路由

实验目的:
观察.研究”递归表查询”的用法.
所有路由表项不必一定指向下一跳路由器.
实验说明:
如上图,所有路由器都配的是静态路由,所以每个路由器上的路由表项都是比较大的.刚开始是经由R2去往R4和R5右边的网络的,现在想要改由经过R3去往那边的网络. 如果用一般的方法,配置静态路由会比较麻烦.因此在这儿用”递归表查询”只需改动一条静态路由,便可以实现要求!
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基本配置:
各个路由器上的静态路由已经配好.
R1:(配置递归表项)
R1(config)#ip route 10.45.2.0 255.255.255.0 10.87.14.4
R1(config)#ip route 10.10.3.0 255.255.255.0 10.87.14.4
R1(config)#ip route 192.168.200.0 255.255.255.0 10.87.14.5
R1(config)#ip route 192.168.150.0 255.255.255.0 10.87.14.5
R1(config)#ip route 10.87.14.0 255.255.255.0 10.23.5.20
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此时R1上的路由表:
R1(config)#do sh ip rou
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
S 192.168.150.0/24 [1/0] via 10.87.14.5
S 192.168.200.0/24 [1/0] via 10.87.14.5
10.0.0.0/24 is subnetted, 4 subnets
S 10.10.3.0 [1/0] via 10.87.14.4
C 10.23.5.0 is directly connected, FastEthernet0/0
S 10.45.2.0 [1/0] via 10.87.14.4
S 10.87.14.0 [1/0] via 10.23.5.20
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通过路由跟踪,可以看到刚开始数据包是经由R2 被转发的:
R1#traceroute 192.168.200.1
Type escape sequence to abort.
Tracing the route to 192.168.200.1
1 10.23.5.20 140 msec 4 msec 80 msec
2 10.23.5.95 104 msec 80 msec 48 msec
3 10.87.14.5 152 msec * 256 msec
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现在在R1上用以下命令让数据包改由R3转发:
R1(config)#no ip route 10.87.14.0 255.255.255.0 10.23.5.20
R1(config)#ip route 10.87.14.0 255.255.255.0 10.23.5.95
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此时再看R1的上路由表:
R1(config)#do sh ip rou
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
S 192.168.150.0/24 [1/0] via 10.87.14.5
S 192.168.200.0/24 [1/0] via 10.87.14.5
10.0.0.0/24 is subnetted, 4 subnets
S 10.10.3.0 [1/0] via 10.87.14.4
C 10.23.5.0 is directly connected, FastEthernet0/0
S 10.45.2.0 [1/0] via 10.87.14.4
S 10.87.14.0 [1/0] via 10.23.5.95
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再通过TRACEROUTE可以看到:
R1(config)#do trace 192.168.200.1
Type escape sequence to abort.
Tracing the route to 192.168.200.1
1 10.23.5.95 24 msec 88 msec 9
2 msec
2 10.87.14.5 164 msec * 164 msec
数据包现在是经由R3转发出去的…
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说明:
实现了以上要求.最重要的是降低了工作量!! 但是递归表查询是比较占路由器资源的. **********************************************。