Routing Protocol Troubleshooting
Troubleshooting steps when dealing with routing protocols
1. Verify connectivity between the two routers by pinging the other router.
– Show interfaces and show IP interfaces will list IP address information.
2. The routing protocol must pass authentication.
– For EIGRP: debug eigrp packets
– For OSPF: debug ospf adj | show ip ospf interface
3. For OSPF, the hello and dead timers must match.
– show ip ospf interface or show IP protocols.
4. Must use the same area for OSPF and ASN number for EIGRP.
– Show ip ospf interface brief | show IP eigrp interface | show ip protocols
5. OSPF router ID’s must be unique.
Reasons OSPFv2 won’t form a neighbourship
1. Interfaces must be in the same subnet.
2. Interfaces must both be up/up.
3. Neighbours must pass authentication.
4. Access-lists must not block OSPF.
5. Hello and dead timers must match.
6. Router ID’s must match.
Default Administrative Distances