Use VM as a VPN Gateway


couldn’t find an option on my old unifi USG to connect to a L2TP VPN server therefore I’m trying to use a VM as a VPN Gateway.

I have a debian 12 VM that is via VPN connected to the other network.
The IP of this VM is and from this VM I can ping
net.ipv4.ip_forward=1 is set and the hypervisor’s firewall is disabled.

The output of “ip route” is:
default dev ppp0 scope link
default via dev ens18 onlink via dev ens18 dev ppp0 proto kernel scope link src dev ens18 proto kernel scope link src

Then I have a static route on my USG-3P router.
Distance: 1
Destination Network:
Type: Next Hop
Next Hop:

If I ping from another PC on my local network, I get this:
PING ( 56(84) bytes of data.
From icmp_seq=2 Redirect Host(New nexthop:

I also tried to set the PS’s gateway to
Pinging in this case has no response.

What did I miss?