Cisco IOS OSPF邻居关系不能正常建立的原因和解决方法(1)

• 关 键 词：
• 数据链路层协议
• 子网掩码

(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)

(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 denied, 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 Ethernet0

R1#show access-list 101

Extended IP access list 101

permit ip 131.108.1.0 0.0.0.3 host 224.0.0.5 (8 matches)

R1#debug ip packet 101 detail

IP packet debugging is on (detailed) for access list 101

R1#

IP: s=131.108.1.1 (local), d=224.0.0.5 (Ethernet0), len 60, sending broad/multicast,

proto

=89

IP: s=131.108.1.2 (Ethernet0), d=224.0.0.5, len 82, access denied, proto=89

IP: s=131.108.1.1 (local), d=224.0.0.5 (Ethernet0), len 60, sending broad/multicast,

proto

=89

IP: s=131.108.1.2 (Ethernet0), d=224.0.0.5, len 82,access denied, proto=89

(5)在broadcast链路上的子网掩码不匹配

(6)Hello/dead 间隔不匹配

(7)认证方式或者是认证密码不匹配

使用debug ip ospf adj 来查看,可以自己使用不同的情况来验证

(8)两台路由器处于不同的AREA

R1#debug ip ospf adj

OSPF adjacency events debugging is on

R1#

OSPF: Rcv pkt from 131.108.1.2, Ethernet0, area 0.0.0.0

mismatch area 0.0.0.1 in the header

R2#show log

%OSPF-4-ERRRCV: Received invalid packet: mismatch area ID, from backbone area must be virtual-link but not found from 131.108.1.1, Ethernet0

(9)Stub/transit/NSSA 区域类型不匹配

这个是常常不小心会被忘记的。

R1#debug ip ospf adj

OSPF adjacency events debugging is on

R1#

OSPF: Rcv hello from 131.108.0.1 area 1 from Ethernet0 131.108.1.2

OSPF: Hello from 131.108.1.2 with mismatched Stub/Transit area option bit

R1#debug ip ospf adj

OSPF adjacency events debugging is on

R1#

OSPF: Rcv hello from 131.108.0.1 area 1 from Ethernet0 131.108.1.2

OSPF: Hello from 131.108.1.2 with mismatched NSSA option bit 更多请看Cisco与华为技术网（Vlan9.com）Cisco IOS、OSPF路由协议专题、Cisco路由器配置手册专题，或进入论坛讨论。