Problem
OSPF is not behaving properly, and you want to debug it to isolate and solve the problem.
Solution
There are several OSPF debugging options. But usually, if there is an OSPF problem, you will see it as instabilities in the neighbor relationships. So the most useful debugging option traces the formation of adjacencies.
Router3#debug ip ospf adj OSPF adjacency events debugging is on Router3#
Discussion
This particular debug output is particularly useful because it helps to diagnose problems when routers fail to form adjacencies with one another. For example, the following debug message indicates that there is an authentication problem. The neighbor router in this case is configured for MD5 authentication, while this router is configured for no authentication.
Dec 21 16:00:14.341: OSPF: Rcv pkt from 172.25.1.7, FastEthernet0/0.1 : Mismatch Authentication type. Input packet specified type 2, we use type 0
Router Configuration and File Management
Router Management
User Access and Privilege Levels
TACACS+
IP Routing
RIP
EIGRP
OSPF
BGP
Frame Relay
Handling Queuing and Congestion
Tunnels and VPNs
Dial Backup
NTP and Time
DLSw
Router Interfaces and Media
Simple Network Management Protocol
Logging
Access-Lists
DHCP
NAT
First Hop Redundancy Protocols
IP Multicast
IP Mobility
IPv6
MPLS
Security
Appendix 1. External Software Packages
Appendix 2. IP Precedence, TOS, and DSCP Classifications
Index