实验名称：作OSPF的AD值修改选择路径 实验拓扑
实验步骤： 配置IP地址 R1: enable conf t int f 0/0 no shu ip add 192.168.12.1 255.255.255.0 exit int l 0 ip add 10.10.1.1 255.255.255.0 exit
R2: enable conf t int f0/1 no shu ip add 192.168.12.2 255.255.255.0 exit int l 0 ip add 10.10.2.2 255.255.255.0 exit int f0/0 no shu ip add 192.168.23.2 255.255.255.0 exit
R3: enable conf t int f0/1 no shu ip add 192.168.23.3 255.255.255.0 exit int l 0 ip add 10.10.3.3 255.255.255.0 exit int f0/0 no shu ip add 192.168.34.3 255.255.0 exit
R4: enable conf t int f0/1 no shu ip add 192.168.34.4 255.255.255.0 exit int l 0 ip add 10.10.4.4 255.255.255.0 exit
配置ospf
R1： router os 1 router-id 1.1.1.1 net 192.168.12.0 0.0.0.255 ar 12 net 10.10.1.0 0.0.0.255 ar 12 exit
R2: router os 1 router-id 2.2.2.2 net 192.168.12.0 0.0.0.255 ar 12 net 192.168.23.0 0.0.0.255 ar 0 net 10.10.2.0 0.0.0.255 ar 0 exit
R3: router os 1 router-id 3.3.3.3 net 192.168.23.0 0.0.0.255 ar 0 net 10.10.3.0 0.0.0.255 ar 0 net 192.168.34.0 0.0.0.255 ar 0 exit
R4: router os 1 router-id 4.4.4.4 net 192.168.34.0 0.0.0.255 ar 0 net 10.10.4.0 0.0.0.255 ar 0 exit
配置路由AD值属性，在R2与R4上建66.1.1.1 修改R4的AD为100，让 路由往R4走
在R2与R4上添加66.1.1.1 R2: int l 66 ip add 66.1.1.1 255.255.255.0 exit router os 1 router-id 2.2.2.2 net 66.1.1.1 0.0.0.0 ar 0 exit
R4: int l 66 ip add 66.1.1.1 255.255.255.0 exit router os 1 router-id 4.4.4.4 net 66.1.1.1 0.0.0.0 ar 0 exit
思路：在R3上做ACL允许 ，修改AD值
R3:
ip access-list standard 66 10 permit 66.1.1.1 exit router os 1 distance 100 4.4.4.4 0.0.0.0 66 exit clear ip os process y show ip route os show ip os database s
