DMVPN issue on a cisco 3845

[harinirina]

Hi all,

We have configured a DMVPN from our headquarter to our branch offices (let's say BR1-BR3) .

We have noticed that sometime we cannot access some of our branch office, the scenario is like this:

- sometime, BR1 and BR2 are down but BR3 is working fine

- sometime, BR2 and BR3 are down but BR1 is working fine

- sometime, BR1 and BR3 are down but BR2 is working fine

- sometime, only one branch office is down and others are working fine

the hub is a cisco 3845, the IOS is c3845-advipservicesk9-mz.124-5c.bin

from the log, we have

*Sep 7 11:28:59.260: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 7: Neighbor x.x.x.x  (Tunnel100) is down: stuck in active

*Sep 7 11:29:01.052: %DUAL-5-NBRCHANGE:  IP-EIGRP(0) 7: Neighbor x.x.x.x (Tunnel100) is up: new adjacency

we do not know why it is down, there is no problem on the connection between the headquarter and branche offices.

Any suggestion are appreciated.

[Javier Portuguez]

Hi,

Please provide some more details.

Are you able to ping from tunnel interface to tunnel interface?

Does the IPsec tunnel come down (show crypto isakmp sa)?

Does the tunnel interface come down (show interface tunnel x or show ip interface brief)?

Any ISAKMP / IPsec related logs during the failure?

How often does it happen?

Does it recover by itself?

Thanks.

Portu.

[harinirina]

Hi Portu,

please, find below the answer:

Are you able to ping from tunnel interface to tunnel interface?

yes, we are able to ping tunnel interface to tunnel interface

Does the IPsec tunnel come down (show crypto isakmp sa)?

no, we see the status is ACTIVE

Does the tunnel interface come down (show interface tunnel x or show ip interface brief)?

the tunnel is UP

Any ISAKMP / IPsec related logs during the failure?

How often does it happen?

sometimes, many times in one day

sometimes, every 1 or 2 days

Does it recover by itself?

yes, it does

but after rebooting devices, it works fine again

Please, let us know if you need more information.