DMVPN Phase 3: Spoke to Spoke dynamic tunnel expires after 5 min

[Romanpreet Singh]

Hi 

I have deployed DMVPN phase 3 and spoke to spoke dynamic tunnels expires after 5 min. Is it default behavior or some command causing it.? Can it be adjusted? 

Config on two spokes is like this:

crypto isakmp policy 1
encr aes
hash sha256
authentication pre-share
group 2
!
crypto isakmp policy 1000
encr aes 256
hash sha256
authentication pre-share
group 2
lifetime 3600

crypto isakmp key XXXXX address 0.0.0.0
crypto isakmp invalid-spi-recovery
crypto isakmp keepalive 60 5

crypto ipsec transform-set XXX esp-aes esp-sha256-hmac
mode transport
!
crypto ipsec profile XXX
set transform-set XXX
!

interface Tunnel21
description DMVPN_Test
ip address 10.X.X.X 255.255.255.0
no ip redirects
ip mtu 1400
ip flow monitor flow-monitor-01 input
ip flow monitor flow-monitor-01 output
ip nhrp map 10.X.X.X Y.Y.Y.Y
ip nhrp map multicast Y.Y.Y.Y
ip nhrp network-id 100
ip nhrp holdtime 300
ip nhrp nhs 10.X.X.X
ip nhrp shortcut
ip nhrp redirect
zone-member security INSIDE
tunnel source GigabitEthernet0/0/1
tunnel mode gre multipoint
tunnel key 100
tunnel protection ipsec profile OIIDMVPN

[Philip D'Ath]

Which router model(s) are you using, and which IOS version?

[Romanpreet Singh]

1st Spoke is 3925 with IOS universalk9.15.1

2nd Spoke is 4331 with IOS UNIVERSALK9 15.4

[Philip D'Ath]

Interesting combination.  For a 3925 a gold star release is 15.4.3M5.  I have also used this software release a lot with DMVPN and had no issues.  Could you change the 3925 to this software release?

On the 4331 I would run the gold star release 3.13.5S (which is 154-3.S5).

[Frank DeNofa]

Romanpreet,

NHRP will tear down dynamic tunnels when traffic has not been routed using the NHRP entry within the configured holdtime. You can see that you have a hold time of 5 minutes (300 seconds) configured on your tunnel interface. If you run 'show ip nhrp' you will see the holdtime decrementing and refreshing when appropriate. Increasing the holdtime will change this behavior.

HTH,

Frank