当业务不通时，如果是OSPF动态路由接入，可以通过交换机，查看设备和交换机的连通性。
操作步骤
- 执行如下命令，登录交换机控制台。
telnet 交换机IP说明 不同厂商的交换机设备的命令行配置方法有所区别，详细情况可参考厂商的配置手册。本文仅以某一厂商的设备举例说明。 - 执行如下命令，查看链路邻居状态。
show ip ospf neighbor系统显示类似如下，查看State值：OSPF process 1, 8 Neighbors, 8 is Full: Neighbor ID Pri State BFD State Dead Time Address Interface 10.10.**.** 0 Full/ - - 00:00:10 192.168.**.** GigabitEthernet 0/13 10.10.**.** 0 Full/ - - 00:00:10 192.168.**.** GigabitEthernet 0/46 - 执行如下命令，查看OSPF配置信息。
configure terminal router ospf show this系统显示类似如下，查看area和network的IP。
Building configuration... ! router-id 1.1.**.** area 1 nssa translator always default-information-originate no-summary area 2 nssa translator always default-information-originate no-summary area 3 nssa translator always default-information-originate no-summary area 17 nssa translator always default-information-originate no-summary area 18 nssa translator always default-information-originate no-summary area 81 nssa translator always default-information-originate no-summary area 90 nssa translator always default-information-originate no-summary area 91 nssa translator always default-information-originate no-summary network 192.168.**.** 0.0.**.** area 1 network 192.168.**.** 0.0.**.** area 1 network 192.168.**.** 0.0.**.** area 1 network 192.168.**.** 0.0.**.** area 2 network 192.168.**.** 0.0.**.** area 2 network 192.168.**.** 0.0.**.** area 0 network 192.168.**.** 0.0.**.** area 81 network 192.168.**.** 0.0.**.** area 81 network 192.168.**.** 0.0.**.** area 81 network 192.168.**.** 0.0.**.** area 81 network 192.168.**.** 0.0.**.** area 90 network 192.168.**.** 0.0.**.** area 90 network 192.168.**.** 0.0.**.** area 91 network 192.168.**.** 0.0.**.** area 91 network 192.169.**.** 0.0.**.** area 17 network 192.169.**.** 0.0.**.** area 17 network 192.169.**.** 0.0.**.** area 18 network 192.169.**.** 0.0.**.** area 18 ! end - 执行如下命令，查看连接设备的接口状态。
show ip interface brief- up：表示接口正常。
- administratively down ：表示接口上配置了shutdown，执行no shutdown命令，使能shutdown。
- down：一般表示网线没有接好，检查网线连接。
系统显示类似如下：Interface IP-Address(Pri) IP-Address(Sec) Status Protocol GigabitEthernet 0/2 no address no address down down GigabitEthernet 0/7 192.168.**.**/24 no address up up GigabitEthernet 0/11 9.9.**.**/24 no address down down GigabitEthernet 0/12 192.168.**.**/24 no address up up GigabitEthernet 0/13 192.168.**.**/30 no address up up GigabitEthernet 0/15 192.168.**.**/24 no address down down GigabitEthernet 0/20 192.168.**.**/30 no address up up GigabitEthernet 0/22 192.168.**.**/30 192.169.**.**/30 up up 192.168.**.**/24 GigabitEthernet 0/23 192.168.**.**/30 192.169.**.**/30 up up GigabitEthernet 0/27 192.169.**.**/30 no address up up GigabitEthernet 0/28 192.169.**.**/30 no address up up GigabitEthernet 0/29 192.169.**.**/30 192.168.**.**/30 up up 192.169.**.**/30 GigabitEthernet 0/30 192.169.**.**/30 no address up up GigabitEthernet 0/33 192.168.**.**/30 192.168.68.6/30 down down GigabitEthernet 0/35 192.169.**.**/30 no address up up GigabitEthernet 0/36 192.169.**.**/30 no address up up GigabitEthernet 0/37 192.168.**.**/30 192.169.**.**/30 down down 192.168.**.**/30 GigabitEthernet 0/38 192.168.**.**/30 192.169.**.**/30 down down GigabitEthernet 0/39 192.168.**.**/30 192.169.**.**/30 administratively down down 192.168.**.**/30 GigabitEthernet 0/40 192.168.**.**/30 192.169.**.**/30 up up GigabitEthernet 0/43 192.168.**.**/24 no address up up GigabitEthernet 0/45 192.168.**.**/30 no address down down GigabitEthernet 0/46 192.168.**.**/30 no address up up GigabitEthernet 0/48 192.168.**.**/30 no address down down Loopback 0 no address no address up down VLAN 1 no address no address up down VLAN 4 192.168.**.**/24 no address up down VLAN 19 192.168.**.**/30 no address up down VLAN 47 192.168.**.**/24 no address up down VLAN 148 172.16.**.**/24 no address up up - 执行如下命令，查看接口下配置的OSPF协商时间和认证等是否匹配。
interface GigabitEthernet 0/39 show this查看ospf authentication 和ospf message-digest-key对应的认证的参数是否和设备上配置的一致，如果不一致表示设备没有认证，无法建立邻居。
系统显示类似如下：Building configuration... ! poe enable no switchport ip ospf network point-to-point ip ospf authentication message-digest ip ospf message-digest-key 23 md5 888 ip ospf hello-interval 3 ip ospf dead-interval 10 ip ospf priority 0 no ip proxy-arp ip address 192.168.**.** 255.255.255.252 ip address 192.169.**.** 255.255.255.252 secondary ip address 192.168.**.** 255.255.255.252 secondary ! end2 secondary