We are using several Routerboards (mainly RB750G) at our town for broadband internet access through FFTB. They are all configured as L2TP Client. Everything works well, but after some time of working (varies from hours to a week) the L2TP interface drops all incoming connections, while outgoing connection from LAN through RB L2TP Client interface continues working. Enabling/disabling L2TP Client interface doesn't helps, only rebooting RB or disabling/enabling ethernet interface on which L2TP connection made.

RouterOS versions tested: 4.9, 4.10, 4.11, 4.13, 5.0rc2. The problem occurs randomly on every RB after some time.

Best regards,
Frank Kontrosh