IP tunnel going up-down every 30s

Hi all,

Weird issue which I can’t seem to diagnose. I have a site-to-site IPIP tunnel with IPsec between a RB1100AHx2 and a RB951G.

On the RB1100AHx2 the log shows 30s after the tunnel interface is up, the interface is going down. 30s later the tunnel is up again:

13:31:21 interface,info ipip3 link up 
13:31:51 interface,info ipip3 link down 
13:32:21 interface,info ipip3 link up 
13:32:51 interface,info ipip3 link down 
13:33:21 interface,info ipip3 link up 
13:33:51 interface,info ipip3 link down 
13:34:21 interface,info ipip3 link up 
13:34:51 interface,info ipip3 link down 
13:35:21 interface,info ipip3 link up 
13:35:51 interface,info ipip3 link down 
13:36:21 interface,info ipip3 link up 
13:36:51 interface,info ipip3 link down 
13:37:21 interface,info ipip3 link up 
13:37:51 interface,info ipip3 link down 
13:38:21 interface,info ipip3 link up 
13:38:51 interface,info ipip3 link down 
13:39:21 interface,info ipip3 link up 
13:39:51 interface,info ipip3 link down 
13:40:21 interface,info ipip3 link up 
13:40:51 interface,info ipip3 link down 
13:41:21 interface,info ipip3 link up 
13:41:51 interface,info ipip3 link down 
13:42:21 interface,info ipip3 link up 
13:42:51 interface,info ipip3 link down 
13:43:21 interface,info ipip3 link up 
13:43:51 interface,info ipip3 link down 
13:44:21 interface,info ipip3 link up 
13:44:51 interface,info ipip3 link down 
13:45:21 interface,info ipip3 link up 
13:45:51 interface,info ipip3 link down 
13:46:21 interface,info ipip3 link up 
13:46:51 interface,info ipip3 link down

The log on the RB951G side shows no evidence of the IPIP tunnel dropping.

Both devices are running RouterOS 6.22. During the time the tunnel is down, no traffic is passing through the tunnel. When the tunnel is up traffic is flowing without a problem. When keeping traffic running (e.g. having a Winbox connection established or having a ping running) the tunnel is staying up. Tried lowering the MTU from 1480 to 1380 to no avail. Clocks are synched. IPIP and IPsec configs are double checked and match (opposite of course).

On the RB1100AHx2 I have multiple tunnels running with a similar configuration to various other devices (another RB1100AHx2, an EdgeRouter Lite) which do not seem to be affected.

Any ideas?

anyone? :confused:

Hello magchiel,

Did you manage to solve this issue?

The tunnel in my case is working but sometimes not and I want to figure it out why does this happen.

My log:

15:02:31 interface,info Tunnel-RDDN link up
15:04:13 interface,info Tunnel-RDDN link down
15:04:40 interface,info Tunnel-RDDN link up
15:06:22 interface,info Tunnel-RDDN link down
15:08:00 interface,info Tunnel-RDDN link up
15:09:41 interface,info Tunnel-RDDN link down
15:09:52 interface,info Tunnel-RDDN link up
15:11:34 interface,info Tunnel-RDDN link down
15:13:16 interface,info Tunnel-RDDN link up
15:14:58 interface,info Tunnel-RDDN link down
15:15:04 interface,info Tunnel-RDDN link up
15:16:47 interface,info Tunnel-RDDN link down
15:18:35 interface,info Tunnel-RDDN link up
15:21:57 interface,info Tunnel-RDDN link down
15:24:08 interface,info Tunnel-RDDN link up
15:27:08 interface,info Tunnel-RDDN link down
15:27:56 interface,info Tunnel-RDDN link up
15:32:18 interface,info Tunnel-RDDN link down
15:35:08 interface,info Tunnel-RDDN link up
15:37:29 interface,info Tunnel-RDDN link down