I have an OpenL2TP VPN instance running to a company providing me with connections to cellphone modems in the 10.4.2.0/24 private IP range. This server is on the same private network as three other web servers that need to be able to send traffic to the same range via the VPN connection on this one machine.
I created the route:
sudo route add -net 10.4.2.0 netmask 255.255.255.0 gw [private vpn server local address] dev eth0
But that doesn't route the traffic once it gets to the vpn server, or at least it doesn't route it back.
How do I route this traffic two-way from the three servers to the VPN server?