Is there a way to set up firewall rules, that would only allow connection if it's encrypted? I'm asking this because to be able to use IPSec/L2TP I have to allow L2TP (UDP 1701) port for incoming connections on public interface. However there is no way I can make sure that L2TP connection is actually encrypted by IPSec. There was similar problem addressed in 2009 and it seems that no solution was provided: http://forum.mikrotik.com/viewtopic.php?f=2&t=30189
Any advice is highly appreciated.
Thanks.
grg