Problem with the interface Tunnel UP/DOWN in GRE DMVPN.

[elmoutaallikbillahtaha]

Hi Everyone

I have a DMVPN Topology, and while configuring the GRE tunnel interface, I have this 

errors appears 

%ADJ-5-PARENT: Midchain parent maintenance for IP midchain out of Tunnel0, addr 16.16.16.1 - looped chain attempting to stack

and the tunnel interface is going UP/Down

 %DUAL-5-NBRCHANGE: EIGRP-IPv4 11: Neighbor 16.16.16.1 (Tunnel0) is down: Interface PEER-TERMINATION received

 %DUAL-5-NBRCHANGE: EIGRP-IPv4 11: Neighbor 16.16.16.1 (Tunnel0) is up: new adjacency

Do you have any idea why the interface Tunnel is going Down every time?

Thanks.

[Georg Pauwen]

Hello,

are you advertising the tunnel source to the spoke via EIGRP ? Try to remove the tunnel source interface from EIGRP, and check if the problem persists.

Otherwise , post the configs of the hub and the spoke.

[Richard Burts]

I had this symptom at a customer site and opened a case with Cisco TAC about it. What we found is that it is a result of a timing issue in processing an event on the tunnel. The router has learned a default route via EIGRP and installed it in the routing table. Then some event impacts the EIGRP neighbor relationship. ( (Tunnel0) is down: Interface PEER-TERMINATION received)  IOS starts to process the change but has not yet removed the default route from the routing table. IOS attempts to forward a packet using the default route, discovers that it no longer is valid and generates the %ADJ-5-PARENT message. Then processing the changes catches up and the default route is removed and things are back to normal. Then whatever the original event was is resolved, EIGRP hello messages are exchanged and the neighbor relationship is established again.

In the case with my customer we found that if we looked in the logs that shortly before the %ADJ-5-PARENT message there would be a message indicating something happened with the physical interface used as the tunnel source. I wonder if that might be the case here.

HTH

Rick

[elmoutaallikbillahtaha]

Hi Richard

Thank you for for your answers, I appreciat your helpmm and I'm learning lot of things from you.

to explain my situation I'm using GNS3 for the simulation and to prepare the CCNP route certification.

and maybe you are right, the problem is coming from interface.

[Richard Burts]

Thanks for the explanation. It is interesting that this is in GNS3. I am quite sure that the %ADJ-5-PARENT message is a result of the interface going down and not the cause of the interface going down. Are there messages in syslog about recursive routing? It would seem that this may be the cause of the tunnel interface flapping up and down.

HTH

Rick

[elmoutaallikbillahtaha]

Hi

Yes I did it so the config for Tunnel 0 Casa Router

interface Tunnel0
ip address 16.16.16.1 255.255.255.0
no ip redirects
ip mtu 1400
no ip next-hop-self eigrp 11
no ip split-horizon eigrp 11
ip nhrp authentication cisco
ip nhrp map multicast dynamic
ip nhrp network-id 30
ip tcp adjust-mss 1360
tunnel source Ethernet5/0
tunnel mode gre multipoint
tunnel key 1234
!

-----------------------------------------------------------------------------------------

Tunnel 0 marrakech Router 

interface Tunnel0
ip address 16.16.16.2 255.255.255.0
no ip redirects
ip mtu 1400
ip nhrp authentication cisco
ip nhrp map multicast 10.10.10.1
ip nhrp map 16.16.16.1 10.10.10.1
ip nhrp network-id 30
ip nhrp nhs 16.16.16.1
ip tcp adjust-mss 1360
tunnel source Ethernet5/1
tunnel mode gre multipoint
tunnel key 1234

[Georg Pauwen]

Hello,

what are the EIGRP configurations of both routers ?

[elmoutaallikbillahtaha]

Hey,

Router EIGRP 11

network "ID networks"

no auto-summary

* the same configuration for both routers.

[Georg Pauwen]

Hello,

are you advertising the networks configured on the tunnel sources (Ethernet5/0 and Ethernet5/1) in EIGRP ?

[elmoutaallikbillahtaha]

Hi Sir

Sorry for the delay.

Yes I'm advertising this networks in EIGRP.

[Georg Pauwen]

Hello,

post the full configs of the routers, and make sure you do not reach the tunnel destination through the tunnel itself.

[elmoutaallikbillahtaha]

Hi 

Here is t he config 

[Georg Pauwen · Accepted solution]

Hello,

your configuration causes recursive routing. Remove the 10.0.0.0 networks from EIGRP on the CASA router, and 11.0.0.0 from the Marrakech router:

CASA

router eigrp 11
network 16.0.0.0
network 172.16.0.0

Marrakech

router eigrp 11
network 16.0.0.0
network 172.17.0.0

[elmoutaallikbillahtaha]

Hello

Thank you for the answer, but I can't understand why when I'm adding

network 10.0.0.0 causes the recursive routing ??

Thanks again for the correct answer, it's working now.

[paul driver]

Hello

but I can't understand why when I'm adding network 10.0.0.0 causes the recursive routing ??

It because your advertising the source addresses ( which are each other rtrs tunnels destination addresses) in eigrp and the routers see these prefixes in the route table as originating through the tunnel your created

res
Paul