Hello, we use lot of Mikrotiks with USB dongle and L2TP VPN with watchdog resetting Mikrotik when VPN is not established. Sometimes it happens, that fully working Mikrotik suddenly disconnects and never connects back. In this case technicians take Mikrotik to me and when I connect Mikrotik to power supply, I find, that:
L2TP Client interface is from unknown reason disabled
L2TP Client interface has lost its configuration (Connect To, User, Password, Profile are empty and also other interface settings are reset to default).
rest of Mikrotik configuration (firewall, watchdog, all other settings) is intact, it is only necessary to update correct values to L2TP Client interface and everything is working correctly
It happened lot with RB750UPr2 but now it happened also with RB750Gr3, which we prefer because so long awaited full USB reset during reboot.
We have noticed it with RB750UPr2 with firmwares from range 6.36, but we have replaced them by RB750Gr3, latest case was with RB750Gr3 with firmware 6.38.3 few days ago, which I have (after reconfiguration of L2TP client interface) upgraded to 6.38.7. If any other case occurs, I will let you know. This problem was generally observed at RB750UPr2 and now at RB750Gr3, but regardless of hardware, its symptoms are the same - only L2TP client interface is disabled and its configured values are either lost either set to default values. The name of L2TP client interface is not lost, it stays the same as it was configured.
Please after you have lost settings, do not reboot device, generate supout file and send it to support@mikrotik.com. We will try to trace this issue and resolve the problem.
To be honest, it will be very hard to do it, because we have around 200 devices spread all aroud our country, they are part of production system, they collect data and I can not afford to disable watchdog (watchdog pings one internal IP, visible only when VPN is up) at all of them and wait when exactly this problem occurs just becuase it is necessary to have it not restarted because of diagnostics. Maybe we could use some script, which will create supout.rif file as soon as this interface is disabled. But I think that this could be somehow related with frequent reboots of units. We use L2TP VPN also with other devices and I have not noticed such case ever, only with these units with USB dongle.
Hello!
We have absolutely the same problem periodically. The last time it was today on RouterOS 6.40.1. Model: RouterBOARD 941-2nD (hAP lite). We have lost connection with one of our remote devices and when we connected to it locally, all settings in L2TP client were on their defaults and client itself was disabled. Unfortunately we have already rebooted this device and upgraded it to 6.40.3. But I will try to send you supout the next time.
We will have a potential fix included in RouterOS starting from next public 6.41rc release (most likely rc30). Please test it if you can and let us know if fix will help in your case.