Admittedly, my understanding of Linux internal and OpenVPN routing is very limited but I still feel like I’m overcomplicating this problem.
Since there seems to be a handful of ways to solve any networking problem, I would love it if anyone with experience could chime in and provide clarification as to the cleanest and best solution here.
TL;DR - I added two (private, without DHCP/gateways/internet) NIC’s/subnets to the OpenVPN server and am trying to get the VPN clients to be able to ping/access devices on the additional subnets.
Full breakdown:
I have set up an OpenVPN server running on an Ubuntu 22.04 host with an internal IP of 10.0.0.114.
The router/internet/DHCP server is at 10.0.0.1. Connecting to the OpenVPN server works perfectly and I am able to access all other devices on the 10.0.0.0/24 subnet.
Recently I added two additional NIC’s to the OpenVPN server:
- ens192 with a static IP of 10.0.200.2/24
- ens224 with a static IP of 10.0.250.2./24
Neither subnet (10.0.200.0/24 & 10.0.250.2/24) have a DHCP server, default gateway, or internet access. Both are used purely as private VLAN networks for hosts to communicate directly with each other.
SSH'ing into the OpenVPN server I am able to ping and access all devices on the 10.0.200.0/24 and 10.0.250.0/24 subnets successfully.
From the OpenVPN connection, I am only able to access devices on the 10.0.0.0/24 network.
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After trying a bunch of different solutions with routing/bridging/etc, I have done a fresh installation of Ubuntu/OpenVPN. I would love some direction before making a mess of things again.

What is the simplest way to allow VPN clients to access the two additional private subnets?
Thank you so much for your time!