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milkboy33
Beginner

DMVPN Tunnel 0 up, Line Protocol Down

Hi,

   We have a 6 spoke DMVPN setup. Five of the six spokes work fine. On the 6th spoke, a 2911, we have created a Tunnel0. Other spokes and the hubs can ping it's ip, but it can't ping itself. When we do a show interface it shows the Tunnel 0 is up, but the protocol is down. What does that mean? Is it working?

Thanks.

5 REPLIES 5
Marwan ALshawi
Advisor

Make sure the hello of tennuls timeout disabled

Sent from Cisco Technical Support iPhone App

Rozsa Illes
Cisco Employee

Hi,

Some of the reasons I can think of based on the limited information we have:

- tunnel source down or tunnel destination is not reachable

- recursive routing (tunnel destination reachable via the tunnel)

- keepalives being dropped on the path

- GRE keepalives enabled with tunnel protection configured (not supported)

Warm Regards,

Rose

Thanks replying you guys.

We figured out the problem. The spoke actually already has a P2P T1 connection to the Hub office. I just had to add 'mode GRE multipoint' to the Tunnel 0 interface and the tunnel is now live. I'm able to ping 2.2.2.1 and vice versa.

Peter Paluch
Hall of Fame Cisco Employee

Hello Tom,

Thanks for getting back to us with the solution. You are absolutely correct. I must have been blind or something! I guess I am getting old

Anyway, thanks again!

Best regards,

Peter

I have been trying to fix this for a month. (mGRE/NHRP configuration - spoke router: Interface up, protocol down). The only solution had been to reboot the (spoke) router. After less than 24 hours, the tunnel would fail and show protocol down again. My problem was that I had configured KEEPALIVE on the tunnel (with protection configured). WHY O WHY couldn't IOS point out this simple conflict? Even stranger, WHY does the tunnel come up at all after a reboot?

Thank you Rose for your suggestion (without ever seeing my configuration). Thanks also to the #1 support resource - GOOGLE - for finding Rose for me.