OSPF Adjacency stuck in EXCHANGE/EX-START - CISCO 6880

[denniska1996]

hello,

I am facing with a big problem in my cisco switch

I have cisco 6880 switch with an OSPF link to cisco switches

It has been working fine for years and all of a suden the process went down, and is stuck in EXCHANGE/EXSTART states

I have another OSPF link (for redundancy purpose) between these two devices that is still working fine

i check all my switches and all the configuration it's right,

i run the command debug ip ospf on the switch and i have an ERROR about the auth key, but no one touch the configuration, and I try to configure it again but i still have the problem with the adj.

I did the clear ospf process on the switches too and I still have the problem,

Any suggestion ?

[M02@rt37]

Hello @denniska1996 

Do you check OSPF adjacency without auth key ? See if it is UP !

After that ensure to use a key without '@'.

[denniska1996]

I try this and still doesn’t work

[MHM Cisco World]

Can I see 

Show ip ospf traffic 

MHM

[denniska1996]

can’t share this

[MHM Cisco World]

Did you check output of this command 

It only count number there is no IP or key' 

This output help me to guide you where is problem 

MHM

[David Ruess]

Do you have MTU configured the same on interfaces that need to form a neighborship? If not, do you have the MTU-ignore command configured? If so that could be a possible issue.

-Daivd

[denniska1996]

i have a mtu configuration, and its the same on both sides

[paul driver]

Hello
If the adjacency still doesn't come back up after you've removed authentication (both sides) what does the debug ip ospf adj log then?

• Can you ping the other-side of the adjacency ip address successfully?
• Do you have a specified MTU value and if so can you ping the other-side of the adjacency ip address successfully with that MTU value?
• Access-list applied or amended recently?
• Ospf network types compatible?
• Ospf router-ids duplicated?

[denniska1996]

i did it,

the ping was unsuccessfully

the mtu configurations is the same on both sides

the debug ip ospf adj - shows me Mismatch Authentication type

[paul driver]

Hello
iIt shouldn’t complain about mismatch authentication if as youve stated have removed authentication - Unless it’s still applied.maybe at a domain level ?

Can you post the ospf neighbour detail 

sh run | sec router
sh ip ospf
sh ip ospf neighbour xxxx detail

[supunit21]

Running "debug ip ospf adj" should pinpoint the root cause.

[denniska1996]

i run the command debug ip ospf on the switch and i have an ERROR about the auth key, but no one touch the configuration, and I try to configure it again but i still have the problem with the adj.

[MHM Cisco World]

No touch config 

Are any peer upgrade recently?

Why' if device upgrade then it can use different algorithms for auth 

Check this point 

Also do 

Show ip ospf interface details 

See which algorithms ospf use for auth

MHM

[denniska1996]

no the 2 switches are in the same version