Ubuntu Server, connected to third-party VPN, cannot be accessed by an external client connected via another VPN

Setup

  • Ubiquiti UDM Pro w/Network 7.4.162
    • 10.2.2.0/24
  • Server: Ubuntu 20.04 connected to AirPVN
    • eno2 10.2.2.99/32
    • eno1 10.2.2.101/32 (enabled temporarily to test if adding a 2nd network connection would help—it doesn’t)
    • Air VPN setup by importing OpenVPN config file into GUI Settings > Network interface.
$ ip route
default via 10.30.220.1 dev tun0 proto static metric 50
default via 10.2.2.1 dev eno2 proto dhcp metric 100
default via 10.2.2.1 dev eno1 proto dhcp metric 101
10.2.2.0/24 dev eno2 proto kernel scope link src 10.2.2.99 metric 100
10.2.2.0/24 dev eno1 proto kernel scope link src 10.2.2.101 metric 101
10.2.2.1 dev eno2 proto static scope link metric 100
10.30.220.0/24 dev tun0 proto kernel scope link src 10.30.220.26 metric 50
169.254.0.0/16 dev eno2 scope link metric 1000
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1
172.18.0.0/16 dev br-e8acfbc92281 proto kernel scope link src 172.18.0.1 linkdown
184.75.221.42 via 10.2.2.1 dev eno2 proto static metric 100
  • Remote WireGuard Client connected to Ubiquiti UDM Pro
    • 192.168.3.2/32

Descriptions

  • The Ubiquiti UDM Pro is my home router.
  • The Ubuntu Server is at my home, connected to the router.
  • The Remote WireGuard Client is my laptop connected through the internet.

Problem

When outside my home, connected via my WireGuard VPN, I can access every computer, except the Ubuntu server—if the server is connected to AirVPN. If I drop the AirVPN connection, I can connect to the Ubuntu server just fine.

When the server is connected to AirVPN, Other local computers on the 10.2.2.0/24 network cacn access the server fine. But Remote VPN Connections (laptop) cannot. Pinging from my laptop leads to timeout. Turning off the AirVPN, pings immediately respond.

  • I’ve tried adding a 2nd Ethernet connection (10.2.2.101/32), but that didn’t help
  • I’ve tried Adding explicit firewall rules from 192.168.3.2/32 to 10.2.2.99/32 and 10.2.2.101/32 and 10.30.220.0/24. Did not help.

It feels like Ubuntu is responsible for the blocking, not my router.

Question

Is there a way I can allow my Laptop’s WireGuard VPN to connect via my Ubiquiti Router and to my Ubuntu Server, while it is connected to AirVPN? Or is this an intentional mechanic I cannot circumvent?

Thank you.

Asked By: James

||

There is no answer. It just doesn’t work.

Answered By: James