Why does VPN slow down?

Question

VPN

Hello.
That's what interests. In Voronezh, there is a server part of the software, in MSC several. outlets with client software on Redhat.
VPN (IPsec) of the type Mikrotik Server (CCR1009-8G-1S) <-> Mikrotik on TT (RB750r2 (hEX lite)) is organized.
The problem is that I cannot upload files to TT via WinSCP from the server, the speed is 3kb / s. And so with "all Moscow" and one point in Voronezh. Even putty authentication is extremely slow. I tested the grid on the Voronezh TT. I connected the laptop to DHCP, which was distributed by Mikrotik TT, the speed is 2 mb / s at the rate clearly, pings are 30 stable, I tried to connect to the server via RDP - it took 10 minutes to render the desktop. That is, we can conclude that the Internet on the TT works stably at the rate, and the "plug" is in the VPN. DNS'y cost provider, 2 pieces.
Below is the settings for the client Mikrotik TT in MSC (all Mikrotiks are configured similarly, sometimes only the encryption protocol changes):

Answer 1

I struggled for 3 days and searched for the cause, and after publishing it on the Toaster, I immediately found it. The bridge from the PC on the red hat to the internal subnet of the server was not configured. How it even worked, I have no idea. Those. in the firewall there is no forward rule indicating the PC behind the nat and this is solved by the bridge.