Fault-finding OSPF error "Discarding packet"

[n21roadie]

Is there a way of fault finding with ospf error “Discarding packet: locally originated src address = XX.XXX.XX.XX”
this occurs every few mins?

[TheLordOfTheShells]

Hi guy
Have you solved the problem?

[mrz]

If connection tracking is enabled, then add RAW firewall rules for OSPF traffic (in both prerouting and output chains) with action=notrack.

Other common causes:

• Multiple neighbors has the same router-id
• Actual layer2 loop in the network
• If switch is used in between, bad switch may acts as hub, sending multicast packet back to the port the packet was received from.

[georgekaskader]

Or you can add drop firewall rule on input protocol ospf with ip address which is logging discarding packets (It will be IP address of your Router which is reporting problem).
In my case it does work.

[n21roadie]

Not solved yet

@mrz

Other common causes:

• Multiple neighbors has the same router-id - Checked OSPF Neighbours and no duplicates!
• Actual layer2 loop in the network - How do you check for Layer2 loops
• If switch is used in between, bad switch may acts as hub, sending multicast packet back to the port the packet was received from. The discarded packets are coming interfaces not going through a switch !