Help: OSPF neighbor down/up with message: too many retransmissions

[john2201]

Dear all,

Please help me to solve an OSPF issue,

We have 2 routers running GRE tunnel through ISP Layer 2 circuit,

Every 10 min (or more) it appears OSPF down/up logging as below:

Neighbor DOWN: Too many retransmissions

Neighbor DOWN: Ignore timer expired

1. Is the issue can be occurred by a physical problem or ISP problem?

2. How can I permanently fix the issue? 

Thank you all your support!

[Francesco Molino]

Hi

Common issue to this error is a mtu mismatch.

Can you try configuring the command ip ospf mtu-ignore on ospf interfaces on both end building up the osof adjacency?

[john2201]

Hello

As I checked, the command can not solve this issue.

Even, If already configured then we must remove it.

Please check again?

[Georg Pauwen]

Hello,

is the physical link itself stable ? Check the MTU settings (and make sure they match) on both sides.

Try an MTU of 1400 on both tunnels.