Cisco IOS OSPF邻居关系不能正常建立原因和解决

　　稍微对ospf的trouble shooting 总结了一下，有参考也有自己的心得。

　　(1)接口上没有激活ospf

　　就是在network语句的时候没有匹配清楚，比如配置了错误的反掩码不对，在show ip ospf interface的时候不会显示你希望激活的接口

　　使用show ip ospf interface来验证，这时候的邻居表是空的

>R2#show ip ospf neighbor

R2#

　　(2)物理层或者是数据链路层协议down.

　　使用show ip int brief 或者是 show int type nomber会导致ospf packet 封装失败。

　　(3)建立邻居的接口被passive掉

R2#show ip ospf interface Ethernet 0

Ethernet0 is up, line protocol is up

Internet Address 131.108.1.2/24, Area 0

Process ID 1, Router ID 131.108.1.2, Network Type BROADCAST, Cost: 10

Transmit Delay is 1 sec, State DR, Priority 1

Designated Router (ID) 131.108.1.2, Interface address 131.108.1.2

No backup designated router on this network

Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

No Hellos (Passive interface)

Neighbor Count is 0, Adjacent neighbor count is 0

Suppress hello for 0 neighbor(s)