目录
- 实验条件
- 环境配置
- 开始Troubleshooting
-
- 问题1. R5路由器直连口没有开启
- 问题2. R21路由器直连口没有开启
- 问题3. R12路由器直连口没有开启
- 问题4. R21的直连接口被配置成了被动接口
- 问题5. R21路由器的hello时间与R3的不一致
- 问题6. R21路由器与R22的直接接口的IP地址网络不一样(子网掩码不同)
- 问题7. R22与R5接口的OSPF网络类型不一致
- 问题8. R5上BGP的配置没有激活与R4的邻居状态
- 问题9. R12上BGP的配置关闭了与R4的邻居状态
- 问题10. R2的接口没有开启MPLS
- 问题11. R12上没有开启负载均衡
- 问题12. R21上关于194.1.1.1的路由捕获异常
- 问题13. R12上的134.21.21.21路由metric不正确
- 问题14. R21配置了max-metric值、导致路由无效
- 问题15. R3配置了汇总域外的路由且因为他不是ASBR,所以产生了问题
- 问题16:R21的BGP配置,没有将路由的下一跳设置为自己
实验条件
网络拓朴
目标输出
环境配置
在我的资源里可以下载(就在这篇文章的开头也可以下载)
开始Troubleshooting
整体排错的思路如下:
- 检查所有的直连口是否双UP
- 检查所有的IGP启动情况,邻居状态
- 检查所有的BGP的状态(已经配置的邻居是否有起来)
- 根据输出,调整BGP选路参数
第一步检查所有的直连接口是否正常UP,所有可以配置的路由的特权密码都是“cisco
”,
问题1. R5路由器直连口没有开启
问题2. R21路由器直连口没有开启
问题3. R12路由器直连口没有开启
第二步 确保拓扑图中的OSPF都能正常的起邻居
从R1开始排查
1. 根据拓扑图,先确保OSPF协议邻居有关系先起来所有路由器的密码都是cisco, 除了不允许配置的路由器外
从R1开始
R3#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
123.1.1.1 1 FULL/BDR 00:00:37 123.45.67.5 Ethernet0/0
发现R3与R21路由并没有建立邻居关系。查询配置后并无异常
R3#show run | s router ospf
router ospf 12345
router-id 123.3.3.3
area 1 range 134.56.78.0 255.255.255.0
network 123.3.3.3 0.0.0.0 area 0
network 123.45.67.6 0.0.0.0 area 0
network 134.56.78.37 0.0.0.0 area 1
R3#
// 查询R21的路由器
R21(config-if)#do show run | s router
router ospf 12345
router-id 134.21.21.21
max-metric router-lsa
passive-interface default
no passive-interface Ethernet2/0
network 134.21.21.21 0.0.0.0 area 1
network 134.56.78.38 0.0.0.0 area 1
network 134.56.78.48 0.0.0.7 area 1
neighbor 123.3.3.3
问题4. R21的直连接口被配置成了被动接口
ospf下配置了被动接口,这样的话,他不会发出hello包也无法接收路由和hello报文(其它的IGP中的被动接口行为也有所不同,有些可以接收,但无法发出,有些是无法接收也无法发出)
配置R21的OSPF
R21#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R21(config)#router ospf 12345
R21(config-router)#no passive-interface Ethernet1/0
R21(config-router)#no passive-interface Ethernet0/0
R21(config-router)#do show run | s router ospf
router ospf 12345
router-id 134.21.21.21
max-metric router-lsa
passive-interface default
no passive-interface Ethernet0/0
no passive-interface Ethernet1/0
no passive-interface Ethernet2/0
network 134.21.21.21 0.0.0.0 area 1
network 134.56.78.38 0.0.0.0 area 1
network 134.56.78.48 0.0.0.7 area 1
neighbor 123.3.3.3
再次查询R21邻居,发现邻居关系依然没有起来,开启Debug
R21#debug ip ospf hello
OSPF hello debugging is on
R21#
OSPF-12345 HELLO Et2/0: Send hello to 224.0.0.5 area 1 from 134.56.78.50
OSPF-12345 HELLO Et2/0: Rcv hello from 134.22.22.22 area 1 134.56.78.49
OSPF-12345 HELLO Et2/0: Mismatched hello parameters from 134.56.78.49
OSPF-12345 HELLO Et2/0: Dead R 40 C 40, Hello R 10 C 10 Mask R 255.255.255.252 C 255.255.255.248
OSPF-12345 HELLO Et0/0: Rcv hello from 123.3.3.3 area 1 134.56.78.37
OSPF-12345 HELLO Et0/0: Mismatched hello parameters from 134.56.78.37
OSPF-12345 HELLO Et0/0: Dead R 44 C 40, Hello R 11 C 10 Mask R 255.255.255.252 C 255.255.255.252
OSPF-12345 HELLO Et0/0: Send hello to 224.0.0.5 area 1 from 134.56.78.38
OSPF-12345 HELLO Et2/0: Send hello to 224.0.0.5 area 1 from 134.56.78.50
OSPF-12345 HELLO Et2/0: Rcv hello from 134.22.22.22 area 1 134.56.78.49
OSPF-12345 HELLO Et2/0: Mismatched hello parameters from 134.56.78.49
OSPF-12345 HELLO Et2/0: Dead R 40 C 40, Hello R 10 C 10 Mask R 255.255.255.252 C 255.255.255.248
OSPF-12345 HELLO Et0/0: Rcv hello from 123.3.3.3 area 1 134.56.78.37
OSPF-12345 HELLO Et0/0: Mismatched hello parameters from 134.56.78.37
OSPF-12345 HELLO Et0/0: Dead R 44 C 40, Hello R 11 C 10 Mask R 255.255.255.252 C 255.255.255.252
问题5. R21路由器的hello时间与R3的不一致
问题6. R21路由器与R22的直接接口的IP地址网络不一样(子网掩码不同)
在R3上查询配置得到以下内容
R3(config-if)#do show run interface e2/0
Building configuration...
Current configuration : 83 bytes
!
interface Ethernet2/0
ip address 134.56.78.37 255.255.255.252
ip ospf hello-interval 11
duplex auto
end
......
// 修改这个配置
R3#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R3(config)#int e2/0
R3(config-if)#no ip ospf he
R3(config-if)#no ip ospf hello-interval
R3(config-if)#do show ip
%BGP-5-ADJCHANGE: neighbor 134.21.21.21 Up ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
123.1.1.1 1 FULL/BDR 00:00:38 123.45.67.5 Ethernet0/0
134.21.21.21 1 FULL/DR 00:00:39 134.56.78.38 Ethernet2/0
R3(config-if)#
R3与R21邻居关系正常了
再回头检查R22和R21的子网掩码配置
R21#show run interface e2/0
Building configuration...
Current configuration : 83 bytes
!
interface Ethernet2/0
ip address 134.56.78.50 255.255.255.248
duplex auto
end
R21#show run | s router ospf
router ospf 12345
router-id 134.21.21.21
max-metric router-lsa
passive-interface default
no passive-interface Ethernet0/0
no passive-interface Ethernet1/0
no passive-interface Ethernet2/0
network 134.21.21.21 0.0.0.0 area 1
network 134.56.78.38 0.0.0.0 area 1
network 134.56.78.48 0.0.0.7 area 1
neighbor 123.3.3.3
R21#
R22#show run interface e2/0
Building configuration...
Current configuration : 83 bytes
!
interface Ethernet2/0
ip address 134.56.78.49 255.255.255.252
duplex auto
end
R22#show run | s router ospf
router ospf 12345
router-id 134.22.22.22
passive-interface default
no passive-interface Ethernet0/0
no passive-interface Ethernet2/0
network 134.22.22.22 0.0.0.0 area 1
network 134.56.78.42 0.0.0.0 area 1
network 134.56.78.48 0.0.0.7 area 1
R22#
根据OSPF网络的宣告内容,可以确定的是R22的E2/0本意是配置子网掩码长度为29位
因此修改R22的接口IP
R22#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R22(config)#int e2/0
R22(config-if)#ip address 134.56.78.49 255.255.255.248
R21#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
123.3.3.3 1 FULL/BDR 00:00:30 134.56.78.37 Ethernet0/0
134.22.22.22 1 FULL/BDR 00:00:34 134.56.78.49 Ethernet2/0
R22(config-if)#do show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
134.21.21.21 1 FULL/DR 00:00:38 134.56.78.50 Ethernet2/0
123.5.5.5 0 FULL/ - 00:00:32 134.56.78.41 Ethernet0/0
至此R21的OSPF邻居关系也都建立了,也正常了,继续排查BGP的邻居关系
此时发现R22的与R5的邻居关系报错,
%OSPF-4-NET_TYPE_MISMATCH: Received Hello from 123.5.5.5 on Ethernet0/0 indicating a potential
network type mismatch
%OSPF-4-NET_TYPE_MISMATCH: Received Hello from 123.5.5.5 on Ethernet0/0 indicating a potential
network type mismatch
%OSPF-4-NET_TYPE_MISMATCH: Received Hello from 123.5.5.5 on Ethernet0/0 indicating a potential
network type mismatch
提示网络类型不一致
问题7. R22与R5接口的OSPF网络类型不一致
R22#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R22(config)#do show run interface e0/0
Building configuration...
Current configuration : 115 bytes
!
interface Ethernet0/0
ip address 134.56.78.42 255.255.255.252
ip ospf network point-to-point
duplex auto
end
R22(config)#int e0/0
R22(config-if)#no ip ospf network point-to-point
查看路由表,正常学到R22的路由,继续排查BGP邻居状态
R4与R5和R12的邻居状态不正常
R4#show ip bgp summary
......
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
123.5.5.5 4 12345 0 0 1 0 0 never Idle
123.6.6.6 4 12345 535 535 3 0 0 08:03:26 1
123.45.67.44 4 14567 0 0 1 0 0 never Idle
R4#show run | s router bgp
router bgp 12345
bgp router-id 123.4.4.4
bgp log-neighbor-changes
no bgp default ipv4-unicast
neighbor 123.3.3.3 remote-as 12345
neighbor 123.3.3.3 update-source Loopback0
neighbor 123.5.5.5 remote-as 12345
neighbor 123.5.5.5 update-source Loopback0
neighbor 123.6.6.6 remote-as 12345
neighbor 123.6.6.6 update-source Loopback0
neighbor 123.45.67.44 remote-as 14567
!
address-family ipv4
network 125.45.67.24 mask 255.255.255.252
neighbor 123.5.5.5 activate
neighbor 123.5.5.5 next-hop-self
neighbor 123.6.6.6 activate
neighbor 123.6.6.6 next-hop-self
neighbor 123.45.67.44 activate
neighbor 123.45.67.44 route-map MED out
exit-address-family
!
address-family vpnv4
neighbor 123.3.3.3 activate
neighbor 123.3.3.3 send-community extended
neighbor 123.5.5.5 activate
neighbor 123.5.5.5 send-community extended
exit-address-family
!
address-family ipv4 vrf BancoBank_ToHub
neighbor 124.45.67.26 remote-as 65100
neighbor 124.45.67.26 activate
exit-address-family
!
address-family ipv4 vrf BancoBank_ToSpoke
neighbor 123.45.67.26 remote-as 65100
neighbor 123.45.67.26 activate
exit-address-family
查询R5的BGP配置
R5#show run | s router bgp
router bgp 12345
bgp router-id 123.5.5.5
bgp log-neighbor-changes
neighbor IBGP peer-group
neighbor IBGP remote-as 12345
neighbor IBGP update-source Loopback0
neighbor 123.3.3.3 peer-group IBGP
neighbor 123.4.4.4 peer-group IBGP
neighbor 134.21.21.21 peer-group IBGP
neighbor 134.22.22.22 peer-group IBGP
!
address-family ipv4
neighbor IBGP route-reflector-client
neighbor IBGP next-hop-self
neighbor 123.3.3.3 activate
no neighbor 123.4.4.4 activate
neighbor 134.21.21.21 activate
neighbor 134.22.22.22 activate
exit-address-family
!
address-family vpnv4
neighbor IBGP send-community extended
neighbor IBGP route-reflector-client
neighbor 123.3.3.3 activate
neighbor 123.4.4.4 activate
exit-address-family
!
address-family ipv4 vrf BancBank
neighbor 123.65.1.30 remote-as 65101
neighbor 123.65.1.30 activate
exit-address-family
问题8. R5上BGP的配置没有激活与R4的邻居状态
发现R5与R4的邻居状态没有激活 “no neighbor 123.4.4.4 activate”,激活一下
R5#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R5(config)#router bgp 12345
R5(config-router)# address-family ipv4
R5(config-router-af)#neighbor 123.4.4.4 activate
R4与R5的邻居关系起来了,继续查看R4与R12的邻居关系
R12#show run | s router bgp
router bgp 14567
bgp router-id 145.12.12.12
bgp log-neighbor-changes
network 123.45.67.20 mask 255.255.255.252
network 123.45.67.40 mask 255.255.255.248
neighbor 123.45.67.45 remote-as 12345
neighbor 123.45.67.45 shutdown
neighbor 123.45.67.46 remote-as 12345
neighbor 145.11.11.11 remote-as 14567
neighbor 145.11.11.11 update-source Loopback0
neighbor 145.11.11.11 next-hop-self
R12#
问题9. R12上BGP的配置关闭了与R4的邻居状态
R12#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R12(config)#router bgp 14567
R12(config-router)#no neighbor 123.45.67.45 shutdown
R12(config-router)#do show ip bgp summary
BGP router identifier 145.12.12.12, local AS number 14567
BGP table version is 15, main routing table version 15
11 network entries using 1584 bytes of memory
21 path entries using 1764 bytes of memory
9/6 BGP path/bestpath attribute entries using 1440 bytes of memory
2 BGP AS-PATH entries using 48 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 4836 total bytes of memory
BGP activity 11/0 prefixes, 21/0 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
123.45.67.45 4 12345 11 14 15 0 0 00:00:15