What is the best way to connect 2 local networks via the Internet?

Question

Debian

There are 2 networks:
1. A network of a small office (5 PCs), a file washer (samba) on debian is organized on the network, the Internet also rises on debian via pppoe, and then it is distributed via iptables, nat, dhcp. On debian, an l2tp server without ipsec was also raised, earlier remote workers connected there to access the local area.
2. The network where there is a freshly installed Windows server 2016 with a terminal server. The Internet rises on the router (authorization from the provider at the poppy address), the server is registered in the DMZ and all requests come to it. RDP works from any internal or external ip. In this LAN there are still a couple of computers.
The task is to connect both LANs into one network, to make transparent file exchange, network printing, etc.
What is the best way to organize tunnels? C debian connect to WinServer or vice versa?
I want to simplify the life of remote workers as much as possible without damaging the stability of local workers. Ideally, the worker should connect to rdp and communicate with both the file washer on debian and with all other machines on both networks.

Answer 1

I recommend using OpenVPN, it has been working for years :-) You can connect it as a service in Windows. Moreover, we also use openvpn for individual workers. In fact, both PPP and L2TP turned out to be much more stable. One minus, you need to install separately in Windows.
And there are much more pluses, you can throw any subnet on a dedicated computer / router, it is very flexible to configure in terms of encryption, flexible user management, very simple monitoring.
Right here at the moment