L2tp over IPsec rebooting routerboards

Hello,

I am having a weird problem with RouterOS and a few different RB’s ( 2011’s, but also happens on 951-n2 and so on ).

Basically i have 3 sites connected with bridged L2tp interfaces. Everything is working correctly. I have set mrru=1600 and traffic is flowing just fine between the 3 sites

The problem starts when i try to enable IPSec transport mode between the 2 public ip’s. If the mrru of the l2tp interfaces is modified, the L2TP client reboots within ~1 minute. If i leave it disabled, everything works fine ( with ipsec transport mode ).

To sum it up :

Working state 1 :

RTR L2TP Client 1 <------L2TP -------> RTR SRV <------L2TP -------> RTR L2TP Client 2
L2TP ( without set on the interfaces ), bridged to lan bridges. 1600 MRRU on the interfaces.

Working state 2 :

RTR 1 IPSEC Transport Mode <----------> RTR SRV <----------> RTR 2 IPSEC Transport Mode ( on their public ip’s)
RTR L2TP Client 1 <------L2TP -------> RTR SRV <------L2TP -------> RTR L2TP Client 2
L2TP ( without set on the interfaces ), bridged to lan bridges. Disabled MRRU on the interfaces.


Not working state ( the client is rebooting ) :


RTR 1 IPSEC Transport Mode <----------> RTR SRV <----------> RTR 2 IPSEC Transport Mode ( on their public ip’s)
RTR L2TP Client 1 <------L2TP -------> RTR SRV <------L2TP -------> RTR L2TP Client 2
L2TP ( without set on the interfaces ), bridged to lan bridges. 1600 ( or 1500 even ) MRRU on the interfaces.

I can post detailed configs, but i am pretty sure everything is default’ish as far as setting it up from the winbox goes. Even if it’s not, i don’t think a reboot is desired.

This happens on every 6.0 rc and on 5.24 also.

Can anyone test and confirm it, so i know i am not going insane ?

Can anyone tell if this is supposed to work like that ? Any response at all, would be fine. “Works for me fine” etc.

We terminate up to 100 L2TP/IPSec peers on a 1100AHx2.

The clients are MikroTik and Android/Windows. No problems for more than half a year now.

Is it a bridged setup ? With l2tp interfaces being added to bridges ?