Cisco IOS OSPF邻居关系不能正常建立原因和解决

钱塘在线

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 brf 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)
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(4)OSPF的hello组播地址被ACL Block
R1#
interface Ethernet0
ip address 131.108.1.1 255.255.255.0
ip access-group 100 in
!
access-list 100 permit tcp any any
access-list 100 permit udp any any
access-list 101 permit ip 131.108.1.0 0.0.0.255 host 224.0.0.5
R2#
interface Ethernet0
ip address 131.108.1.2 255.255.255.0
ip access-group 100 in
!
access-list 100 permit tcp any any
access-list 100 permit udp any any
access-list 101 permit ip 131.108.1.0 0.0.0.255 host 224.0.0.5
R2#debug ip packet 101 detail
IP packet debugging is on (detailed) for access list 101
IP: s=131.108.1.2 (Ethernet0), d=224.0.0.5, len 68, access dend, proto=89
这时候的邻居关系是INIT
R2#show ip ospf neighbor
Neighbor ID   Pri State    Dead Time   Address       Interface
131.108.2.1    1 INIT/-   00:00:33    131.108.1.1&n
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