System network configuration

My setup is described in the image above. I have a raspberry pi connected to a router via Wi-Fi and the router is connected to a host via a Ethernet cable. The router doesn't have a internet connection -- only internal routing - LAN.

So my question is -- how would I set a simple VPN tunnel on the Raspberry Pi which would be used to route all the incoming and outgoing LAN traffic?

I've looked into PiVPN but that requires an Internet connection and I've also looked into PIA's solution to this, but again, it requires an Internet connection. Other guides for LAN only configurations for VPN tunneling haven't been helpful.

Thanks for any help.

EDIT 8:15 PM - 1/8/19: The host is a Programmable Logic Controller (PLC) which is programmed using Ladder Logic. The purpose of this tunnel would be to encrypt the traffic to and from the raspberry pi. In this way another host inside the LAN e.g. attacker computer, wouldn't be able to sniff or modify the data packets send between the two parties.

3 Answers 3


Do you need VPN? I have made very good experiences using x11vnc. You need to set up an x11vnc server e.g. on RPI and a client, that is, a VNCviewer on the host. In the setting described by you this should work pretty well..

  • @jake but what does a VPN buy the OP? If both machines are on the same subnet a VPN isn't needed. A VPNs primary purpose is to give you remote access to your LAN so you can feel at home (with secure access) from a remote location. VNC (or XRDP (if you must)) gives the OP what he/she requires.
    – Dougie
    Jan 8, 2019 at 22:07
  • @Dougie You're right. Sorry, did no read carefully.
    – jake
    Jan 8, 2019 at 22:09
  • I don't need a VPN per say, but I need the tunnel to be encrypted from point to point (Raspberry Pi to Router). The purpose of this is to prevent another host e.g. attacker computer from sniffing LAN traffic between the raspberry pi and the router among other things.
    – Drop_Cake
    Jan 9, 2019 at 1:12
  • I would like to clarify that the host is a Programmable Logic Controller (PLC) which is programmed using Ladder logic.
    – Drop_Cake
    Jan 9, 2019 at 1:13

you need a ssh tunnel not a vpn this is only a guide that maybe help.

  • Why is a ssh tunnel better than a VPN tunnel? We're looking for long answers that provide some explanation and context. Don't just give a one-line answer; explain why your answer is right, ideally with citations. Answers that don't include explanations may be removed.
    – Ingo
    Jan 9, 2019 at 10:31

There are only answers not to use a VPN tunnel. In principle I agree with that because I think using a virtual private network on a simple local area network without public access for a simple secured point to point connection is overkill. But to answer your question for an OpenVPN you can look at Simple openVPN with static keys. There you can find a simple setup mostly thought as entry point for setting up a VPN. The diagram shows an VPN tunnel through the internet but the first step of the setup is for local testing so you should be able to adopt it for your needs.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.