System information

Troubleshooting TCP/IP 7-121
OSPF: Routers Not Establishing Neighbors
OSPF: Routers Not Establishing Neighbors
Symptom: OSPF routers are not establishing neighbor relationships properly. The result is that
routing information is not exchanged between routers.
Table 7-11 outlines the problems that might cause this symptom and describes solutions to those
problems.
Table 7-11 OSPF: Routers Not Establishing Neighbors
Possible Problem Solution
Misconfigured or
missing network router
configuration command
Step 1 Use the show ip ospf interfaces exec command to determine which
interfaces have OSPF
1
enabled.
Step 2 If the output indicates that an interface that should be running OSPF is
not doing so, use the show running-config privileged exec command to
view the router configuration.
Step 3 Make sure that network router configuration commands are specified for
each interface on which OSPF should run.
For example, if the IP address of Ethernet interface 0 is 192.168.52.42
with a subnet mask of 255.255.255.0, enter the following commands to
enable OSPF on the interface:
c4500(config)#router ospf 100
c4500(config-router)#network 192.168.52.0 0.0.0.255
area 0
Make sure the proper process IDs, addresses, wildcard masks, and other
variables are properly specified. To configure an OSPF routing process,
use the router ospf global configuration command:
router ospf process-id
Syntax Description:
• process-id—Internally used identification parameter for an OSPF
routing process. It is locally assigned and can be any positive integer. A
unique value is assigned for each OSPF routing process.
Note: There is no correlation between OSPF wildcard masks (used in
OSPF network commands) and the subnet mask configured as part of an
interface IP address.
Step 4 Check other OSPF routers on the network using the preceding steps.
Make sure that OSPF is configured properly on all neighboring routers so
that neighbor relationships can be established.