I am having trouble with either PPTP or L2TP connections between two Mikrotik routers. Both are connected to the internet. In either case the connection between the routers will come up and traffic will flow successfully. I want to keep the connection up continuously. But exactly 60 seconds after traffic stops the connection goes down and then immediately reconnects. This continues to happen indefinitely if there is no traffic. When I turn on logging for PPTP or L2TP I can see that a keep-alive message (echo-request/reply (PPTP) or HELLO/HELLO (L2TP)) is taking place every 60 seconds, but the link still goes down exactly 60 seconds after the last “real” traffic takes place, even if the keep-alive just happened a few seconds earlier.
Interestingly the keep-alive messages are NOT affected by the setting of the keep alive timer in the L2TP or PPTP client settings. Regardless of the value of that timer, the messages take place every 60 seconds.
I also notice when I turn on logging details for L2TP or PPTP that when the link goes down exactly 60 seconds after the last real traffic, the first message in the log in either case is “LCP Close”. So it looks like some sort of LCP timeout, but I cannot find any way to fix it. This happens even though I do see the LCP echo requests and replies from the server in the log.
This is all happening on the client side…I’ve tried changing things on the server side, also without success. It appears to be the client that is taking down the connection and then reconnecting immediately.
I’ve also tried disabling fast track. It makes no difference.
Any suggestions would be greatly appreciated.