Sending Data over the Airwaves
Choosing Network Technologies: Physical Connection
Network Firewalls: Defending Data with the DMZ

Debugging Open Shortest Path First (OSPF) Routing Protocol

Now, it is time to move on to the infamous debug commands that are available to Open Shortest Path First (OSPF) routing protocol. As with the show command, the debug command has many options. Because spreading the net too widely can cause a lot of information to sift through, you want to make the scope of the command as narrow as possible. Unlike other debugging commands, there is not a general debug ip ospf, so you are forced to be a little selective.

Router2>enable
Password:
Router2#debug ip ospf ?
  adj             OSPF adjacency events
  database-timer  OSPF database timer
  events          OSPF events
  flood           OSPF flooding
  hello           OSPF hello events
  lsa-generation  OSPF lsa generation
  mpls            OSPF MPLS
  nsf             OSPF non-stop forwarding events
  packet          OSPF packets
  retransmission  OSPF retransmission events
  spf             OSPF spf
  tree            OSPF database tree

The events option is just about the most general option among the available options. The output that follows shows these options:

  • The router is sending Hello packets out to the multicast address on one of its network interfaces.

  • The router is selected as the Designated Router.

  • The router found a route to 192.168.10.0/24 from one of its neighbors.

Router2>enable
Password:
Router2#debug ip ospf events
OSPF events debugging is on
*Mar 18 02:58:36.069: OSPF: Interface FastEthernet0/0 going Up
*Mar 18 02:58:36.069: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.1.240
*Mar 18 02:58:46.069: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.1.240exit
*Mar 18 02:58:56.069: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.1.240
*Mar 18 02:59:06.069: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.1.240
*Mar 18 02:59:16.069: OSPF: end of Wait on interface FastEthernet0/0
*Mar 18 02:59:16.069: OSPF: DR/BDR election on FastEthernet0/0
*Mar 18 02:59:16.069: OSPF: Elect BDR 192.168.5.1
*Mar 18 02:59:16.069: OSPF: Elect DR 192.168.5.1
*Mar 18 02:59:16.069: OSPF: Elect BDR 0.0.0.0
*Mar 18 02:59:16.069: OSPF: Elect DR 192.168.5.1
*Mar 18 02:59:16.069:        DR: 192.168.5.1 (Id)   BDR: none
*Mar 18 02:59:16.069: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.1.240
*Mar 18 03:25:46.084: %OSPF-5-ADJCHG: Process 100, Nbr 192.168.10.1 on FastEthernet0/0 from LOADING to FULL, Loading Done
Router2#no debug ip ospf events
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Network Basics: Network Destination Addresses
Observing Dynamic Host Configuration Protocol (DHCP) Traffic
Setting Up Cisco Device Timeouts
Working with Enhanced Interior Gateway Routing Protocol (EIGRP)
Cisco Networking: Physical Layer Troubleshooting
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