How to isolate interfaces on a wireguard proxy server

hKaspy

2/12/24, 8:49 PM

I have a Wireguard server that I want to act as a public proxy to all my WG VPNs.

My first wg config (wg0) is a standard road warrior scenario. This is the setup:

ProxyPeer - wg0 address 10.0.0.1, publicly reachable
LANPeer - inside of LAN 192.168.150.0/24, using NAT, wg0 address 10.0.0.2
MobilePeer - wg0 address 10.0.0.3

This is working well - I can connect from MobilePeer to ProxyPeer and ping anything in LAN using the LANPeer no problem.

Now I want to add a secong config (wg1) to ProxyPeer, that allows me to bridge two LANs like so:

ProxyPeer - wg1 address 10.1.0.1, publicly reachable
LANPeer - the same LANPeer as in wg0, but with wg1 address 10.1.0.2
OfficePeer - wg1 address 10.1.0.3, inside of LAN 172.16.1.0/24

Now when I try to start the wg1 interface in ProxyPeer, it fails with the following error (taken from sysctl status wg-quick@wg1):

Feb 12 20:28:39 debian wg-quick[19307]: [#] ip -4 route add 192.168.150.0/24 dev wg1
Feb 12 20:28:39 debian wg-quick[19372]: RTNETLINK answers: File exists

I know it's becuase I have AllowedIPs = 192.168.150.0/24 for the LANPeer, but that's what I need.

Any ideas how to fix this?

I've tried adding (on ProxyPeer) Table = 100 to wg0 interface and Table = 101 to wg1, but that broke event the working wg0 setup.

103

0 + 5

route

wireguard

vidarlo

2/12/24, 8:55 PM

Why do you want to reuse subnets like that? It's a recipe for disaster.

hKaspy

2/13/24, 7:39 AM

It's one peer (NATed) in one subnet trying to be in two VPNs together.

vidarlo

2/13/24, 7:56 AM

Why not use different subnets for... each subnet?

hKaspy

2/13/24, 9:32 AM

Apologies, I've edited the question to better explain what I'm trying to do.

djdomi

2/13/24, 12:50 PM

if more as one vpn is used, use subnet ting and route to the targets

Elon Musk

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

EN: How to isolate interfaces on a wireguard proxy server

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