用分发列表过滤掉路由更新，以达到路由筛选的目的

一、拓扑图：

 

二、配置各路由器的 IP和协议，然后在 R2上做重分发。保证两边都能学到各自的路由，为了学到的全部都是明细路由，以体现实验效果。我们把 R2和 R3的 RIP V2都 关闭自动汇总，

1、下面看一下 R1的 route:

 

R1#sh ip route 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        172.168.0.0/24 is subnetted, 4 subnets C       172.168.0.0 is directly connected, Loopback0 C       172.168.1.0 is directly connected, Loopback0 C       172.168.2.0 is directly connected, Loopback0 C       172.168.3.0 is directly connected, Loopback0      172.16.0.0/24 is subnetted, 1 subnets C       172.16.255.0 is directly connected, Serial1/1 O E2 192.168.255.0/24 [110/200] via 172.16.255.2, 00:00:03, Serial1/1 O E2 192.168.0.0/24 [110/200] via 172.16.255.2, 00:00:03, Serial1/1 O E2 192.168.1.0/24 [110/200] via 172.16.255.2, 00:00:03, Serial1/1 O E2 192.168.2.0/24 [110/200] via 172.16.255.2, 00:00:03, Serial1/1 O E2 192.168.3.0/24 [110/200] via 172.16.255.2, 00:00:03, Serial1/1

 

2、再来看一下 R3的路由表：

 

R3#show ip route 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        172.168.0.0/16 is variably subnetted, 4 subnets, 2 masks R       172.168.1.0/24 [120/10] via 192.168.255.2, 00:00:02, Serial1/0 R       172.168.0.1/32 [120/10] via 192.168.255.2, 00:00:02, Serial1/0 R       172.168.2.0/24 [120/10] via 192.168.255.2, 00:00:02, Serial1/0 R       172.168.3.0/24 [120/10] via 192.168.255.2, 00:00:02, Serial1/0      172.16.0.0/24 is subnetted, 1 subnets R       172.16.255.0 [120/10] via 192.168.255.2, 00:00:02, Serial1/0 C    192.168.255.0/24 is directly connected, Serial1/0 C    192.168.0.0/24 is directly connected, Loopback0 C    192.168.1.0/24 is directly connected, Loopback0 C    192.168.2.0/24 is directly connected, Loopback0 C    192.168.3.0/24 is directly connected, Loopback0

 

3、现在两边明细路由都有了，那么现在我要用 distribute的命令过滤特定路由条目。不过在这之前我们要建立访问控制列表。

 

4、在 R2上 distribute针对 ospf区域的 RIP发进来的路由，以过滤掉 192.168.2.0/24和 192.168.3.0/24的网络：

R2(config)#access-list 1 deny 192.168.2.0 0.0.0.255 R2(config)#access-list 1 deny 192.168.3.0 0.0.0.255 R2(config)#access-list 1 permit any  ( 这一条一定要加上，不然的话会全部过滤掉RIP来的路由) R2(config-router)# router ospf 1 R2(config-router)#distribute-list 1 out rip ( 对外部RIP路由进行distribute,引用访问控制列表1)

5、再来看一下 R1的路由表：

R1#show ip route 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        172.168.0.0/24 is subnetted, 4 subnets C       172.168.0.0 is directly connected, Loopback0 C       172.168.1.0 is directly connected, Loopback0 C       172.168.2.0 is directly connected, Loopback0 C       172.168.3.0 is directly connected, Loopback0      172.16.0.0/24 is subnetted, 1 subnets C       172.16.255.0 is directly connected, Serial1/1 O E2 192.168.255.0/24 [110/200] via 172.16.255.2, 00:01:31, Serial1/1 O E2 192.168.0.0/24 [110/200] via 172.16.255.2, 00:01:31, Serial1/1 O E2 192.168.1.0/24 [110/200] via 172.16.255.2, 00:01:31, Serial1/1 (现在只能学到这三条路由了 ,过滤掉了 192.168.2.0和 192.168.3.0这两个网络 )

6、我们再在 R2上 distribute针对 RIP区域的 OSPF发进来的路由，以过滤掉 172.168.0.0/24和 172.168.1.0/24的网络：

R2(config)#access-list 2 deny 172.168.0.0 0.0.0.255 (建立一个列表 2对源地址的过滤 ) R2(config)#access-list 2 deny 172.168.1.0 0.0.0.255 (建立一个列表 2对源地址的过滤 ) R2(config)#access-list 2 permit any  ( 切记不要忘了加这一条，不然所有路由都学不到) R2(config-router)# router rip R2(config-router)#distribute-list 2 out ospf 1( 对外部ospf路由进行distribute,引用访问控制列表2)

7、下面我再来看一下 R3的路由表：

R3#show ip route 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        172.168.0.0/24 is subnetted, 2 subnets R       172.168.2.0 [120/10] via 192.168.255.2, 00:00:01, Serial1/0   R       172.168.3.0 [120/10] via 192.168.255.2, 00:00:01, Serial1/0   (只有这两条路由了 )      172.16.0.0/24 is subnetted, 1 subnets R       172.16.255.0 [120/10] via 192.168.255.2, 00:00:01, Serial1/0 C    192.168.255.0/24 is directly connected, Serial1/0 C    192.168.0.0/24 is directly connected, Loopback0 C    192.168.1.0/24 is directly connected, Loopback0 C    192.168.2.0/24 is directly connected, Loopback0 C    192.168.3.0/24 is directly connected, Loopback0 R3#

 

通过上面的图示可以看到 172.168.0.0/24和 172.168.1.0/24的网络已经被过滤掉了。