How to provide Internet access through the Kerio-Mikrotik tunnel?

Question

Mikrotik

Kerio Connect 9 server with Internet access. Configured as an opaque proxy.
Customers behind Mikrotik RB751 .
The task is to provide Internet to clients for Mikrotik without authorization and, if possible, without the need to configure anything on the target PCs.
The first thing that comes to mind is to create an L2TP tunnel, and wrap traffic 0.0.0.0/0 in the tunnel in Mikrotik routes.
However, it is not clear how to configure Kerio to send Internet traffic without authorization. It also works as an opaque proxy, and you have to specify a proxy:port in the client settings for Kerio.
How to solve this problem with given conditions?
Thanks in advance.

Answer 1

If there is access to the Kerio settings, the task seems to be solved, otherwise there will be difficulties.