Local LAN RDP to OpenVPN Client Connected to Remote Network

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Joined: Tue Sep 04, 2018 4:46 pm

Local LAN RDP to OpenVPN Client Connected to Remote Network

Post by shar1831 » Tue Sep 04, 2018 5:18 pm

Hi everyone,

I've got a specific scenario that I'm wondering if I can get your help with.

Here is a summary of my setup:
Server: OpenVPN hosting two tunnels: Both are routed tunnels where one is a split tunnel, and the other routes all remote traffic through it. These two tunnels are fully independent of each other and I've set them up as backup access paths for myself to get into my network if one of the tunnels fail.
Client: OpenVPN on a Windows 10 laptop.

Here's my scenario:
From an OpenVPN perspective, everything works. When I am on a remote network outside my home, I can VPN in and access everything I need to. Both routed and split-tunnel allow me to access my home network resources.

However, my most common usage scenario when I'm on a remote network is that I would be on a desktop machine on the same network as the laptop. I would RDP from the desktop to the laptop, and from the laptop initiate a VPN connection. In effect, I am doing this:

From Workstation on remote network RDP to Laptop (Laptop is on the same network as Workstation), and then from Laptop VPN to Home Network.

Here's my problem:
It is is the RDP session that I'm currently having problems with. In the past, I have been able to RDP from workstation to the laptop, and initiate my VPN connection back home. I would be able to maintain my RDP session to my laptop, and using the laptop, access files and resources from my home network. Then one day, I formatted my laptop. Since then, I have had issues with this RDP session.

Using the split-tunnel, I can use my workstation to RDP to the laptop, establish my VPN session back home, and access my files. The issue is that my traffic is no longer routed through my home network. This is what I want.

Using the routed tunnel, I can use my workstation to RDP to the laptop, but as soon as my VPN session is established, the RDP session drops while the VPN tunnel session persists. I know just enough about networking to know that in a routed setup, OpenVPN has replaced my default route so that the RDP session coming from my workstation doesn't know where to go, and subsequently causes the RDP session to fail. The OpenVPN session will continue to function.

What I don't know is how to fix this. This is where I'm hoping to get guidance from anyone on this forum.

I don't know how my system was set up initially that allowed the RDP session to be maintained over a routed connection (I even did a bridged connection at one point in the past and I remember that to work.) My workstation hasn't changed, my OpenVPN server hasn't changed. The only thing that was changed was I formatted my Windows 10 laptop and reused my backed-up OpenVPN configuration. I don't know what else could have been different on that Windows laptop that would allow the incoming RDP session to be maintained over a routed or bridge connection.

Does anyone have any ideas? I've turned off Windows Firewall as a primary step, I haven't dared play with interface metrics yet, and I've tried to add static routes (but maybe my network knowledge is not strong enough to troubleshoot routing).

If there's anything that I can add to help troubleshoot, please ask and I'll provide as much info as I can.

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Re: Local LAN RDP to OpenVPN Client Connected to Remote Network

Post by TinCanTech » Tue Sep 04, 2018 6:17 pm

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