Multiple Site-To-Site VPNs to one OpenVPN Server

Roemer

8/10/24, 10:17 PM

I am struggling to setup multiple site-to-site vpns.

I have 3 sites:

Site A: OpenVPN Server, inside OPNsense, IP Ranges: 192.168.10.0/24
Site B: Asus Router with Fresh-Tomato, IP Ranges: 192.168.20.0/24
Site C: Asus Stock Router, IP Ranges: 192.168.30.0/24

I managed to setup an OpenVPN Server in OPNsense with the following:

IPv4 Tunnel Network: 10.10.1.0/24
IPv4 Local Network: 192.168.10.0/24,192.168.20.0/24
IPv4 Remote Network: 192.168.20.0/24

And also a client specific override for Client B with:

IPv4 Remote Network: 192.168.20.0/24

With that setup, I was able to connect site B to the server on site A and can access the ips of site A from site B and the other way around. I am not sure if all that configs are needed or if some could be skipped but I was happy to get it working.

Now I also want to add site C as client to site A.

I tried reusing the same OpenVPN server for site C and just extended IPv4 Local Network, IPv4 Remote Network and added a separate client specific override for the range of C: 192.168.30.0/24

Uppon doing that, site C fails to connect to A with Conflicting Routing Rules.

Is is possible to add multiple site-to-site to one instance of an OpenVPN server at all or does each one need a separate server? If it is possible, what am I missing? Also, is the other configuration ok like this?

0 + 2

vpn

openvpn

site-to-site-vpn

opnsense

George Y

8/11/24, 2:35 AM

I believe that the "overriding" makes trouble - you have duplicate definition on '192.168.2.0/24'.

Roemer

8/11/24, 7:09 AM

Thanks for your response. But I do the same for site B which works.

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Multiple Site-To-Site VPNs to one OpenVPN Server

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