How do I set up routing between two LANs on a VPN connection?

Question

VPN

Essence: there are two offices, in both gateways there are mikrotiks that connect via PPTP, one of them is a PPTP server.
Head office addresses: 192.168.71.0/24
Branch addresses: 192.168.80.0/24
VPN addresses: 172.16.30.1 and 172.16.30.2 respectively.
Routes:
Server:

#      DST-ADDRESS        PREF-SRC        GATEWAY            DISTANCE
 0 ADS  0.0.0.0/0                          inet                      1
 1 ADC  10.1.255.255/32    xxx.xxx.xx.xxx  inet                      0
 2 ADC  172.16.30.2/32     172.16.30.1     <pptp-client>             0
 3 ADC  192.168.71.0/24    192.168.71.1    bridge_main               0
 4 A S  192.168.80.0/24    192.168.71.1    172.16.30.2               1

Customer:

#      DST-ADDRESS        PREF-SRC        GATEWAY            DISTANCE
 0 ADS  0.0.0.0/0                          192.168.20.1              1
 1 A S  172.16.30.0/24                     pptp-to-srv               1
 2 ADC  172.16.30.1/32     172.16.30.2     pptp-to-srv               0
 3 ADC  192.168.20.0/24    192.168.20.60   ether1                    0
 4 A S  192.168.71.0/24    192.168.80.1    pptp-to-srv               1
 5 ADC  192.168.80.0/24    192.168.80.1    bridge1                   0

The fact is that PCs from any segment see everything up to the remote gateway, and then - plugging. What to do - I will not put my mind to it. It is necessary that the balls from different segments open.

Answer 1

I myself will answer. In my case, the masquerading on the server was set to a specific interface, and that was the problem.