拓扑图：
无配置分发列表前：
R2:
router ospf 1
redistribute rip metric 100 metric-type 1
subnets
network 192.168.12.0 0.0.0.255 area 0
router rip
version 2
redistribute ospf 1 metric 3
network 200.168.23.0
no
auto-summary
R3：
r3#sh ip rou
R 192.168.12.0/24 [120/3] via 200.168.23.1,
00:00:08, Ethernet0/1
C
200.168.23.0/24 is directly connected, Ethernet0/1
192.168.110.0/32 is subnetted, 1 subnets
R 192.168.110.1 [120/3] via 200.168.23.1,
00:00:08, Ethernet0/1
C
192.168.200.0/24 is directly connected, Loopback0
192.168.100.0/32 is subnetted, 1 subnets
R 192.168.100.1 [120/3] via 200.168.23.1,
00:00:08, Ethernet0/1
r3#
可以看出R3学习到了所有的OSPF网络中的路由，现在配置路由过渡，只允许192.168.100.0/24这条路由被R3学习到，其它的不允许！
R2：加上：
router rip
distribute-list 10 out ospf 1
access-list 10 permit 192.168.100.0
0.0.0.255
R3:可能要等时间久一点才会有反应：
r3#sh ip rou
C
200.168.23.0/24 is directly connected, Ethernet0/1
C
192.168.200.0/24 is directly connected, Loopback0
192.168.100.0/32 is subnetted, 1 subnets
R 192.168.100.1 [120/3] via 200.168.23.1,
00:00:01, Ethernet0/1
r3#
可以看出只有192.168.100.0/24这条路由被R3学习到，配置成功！！！
