I configured as you described above,
but unfortunately I had no luck, a connection was not established.
When I try to connect via vpn address of the RB interface within the LAN (vpn server address 192.168.178.201)
a valid connection is established, but not from WAN (public IP).
I forgot to mention that the DSL Router (FritzBox) is configured to forward the ports TCP 1723 and GRE to the
RB interface (192.168.178.201).
Maybe this could be a problem?
Thanks a lot for your help, cheers, Mike.
I hope I figured out what does the trick...:
Adding a static route to define a standard gateway to reach the internet.
I found it while tying to configure a NTP time server, which wasn't reached

# DST-ADDRESS PREF-SRC GATEWAY DISTANCE
0 A S 0.0.0.0/0 192.168.178.1 1
1 ADC 192.168.178.0/24 192.168.178.201 ether5-LAN-rau 0
Next step will be to enable L2TP and IPSec...
You do not have the required permissions to view the files attached to this post.