Simple Masquerade of Machines on Network through a WAN Interface
Need a simple (no firewall) isolated network within your network where those machines need to "talk outside".
My use case is a stand alone IOT system that had more than one host machine. By isolating that with a "gateway" sbc with dual nic (used usb/ethernet) I can have consistent IP addressing no matter where the system is deployed.
This really is only appropriate within a private LAN. If the WAN side is going to be public facing then you need a more robust firewall like firehol.
Included in repo are three bash scripts and Systemd Service file.
edit the scripts changing the wan/lan Nic names
edit service file changing the path to scripts
link or copy the service file to
Then to start, stop, persist
sudo systemctl start masquerade sudo systemctl stop masquerade sudo systemctl enable masquerade
try starting the service then ping something "outside" from a host "inside" (not the gateway)
if it works then enable it and you are set.
inspired by this post https://superuser.com/a/939657/430020