Cisco ACI OSPF Neighbor Failer and INIT state

[Translator]

I set up OSPF between Cisco ACI N9K-C93180YC-EX switch and C9300-48U switch, but Neighbor state is maintained in INIT and will not be established. I will attach the setting screen as a capture screen. Can you tell me what the problem is? Two Nexus switches have vPC settings

[RedNectar]

Hi @Translator ,

Try setting MTU in the L3Out to 1500 bytes.

[Translator]

I set the MTU to 1500 in SVI, is it different from the L3OUT MTU 1500 you answered?

[RedNectar]

Hi @Translator ,

No, I was referring to the MTU in the SVI - so we need to look at other options. Have you tried running debug  on the external router?

[Translator]

I checked and it's repeating like this

[RedNectar]

Hi @Translator ,

OK. I guess you need to double check all those OSPF settings that have to match. I can see that the IPs seem to be on the same subnet, but I can't check (from what you've shown)

• That the mask /24 at BOTH ends
• that the OSPF area ID is the same at both ends

And at the very basic level, I guess you've already tested that you can ping from one end to the other.