How to create a virtual IP (NAT) for a device on another computer?

Ubuntu Linux computer has two network interfaces:

wlx1cbfce8bd2bd: inet 10.1.1.129 netmask 255.255.255.0

on this network, there is a device: 10.1.1.10 - with a UDP port 10000 that I wish to make accessible from the internet.

the second interface is....(this is connected to Fortigate)

enp4s0: inet 192.168.1.80 netmask 255.255.255.0

Fortigate LAN IP is: 192.168.1.1

I wish to enable somebody to connect to the UDP port 10000 of the 10.1.1.10 device from the internet.

I do know how to set up NAT(Virtual IP) and IP4Policy to forward traffic to 192.168.1.80 - but I do not know how to do it to 10.1.1.10

I assume I need route(s) on Fortigate, as well as on my PC (192.168.1.80) and som eiptables? to achieve that.

Best answer by akristof

Hello,

Thank you for your question.

It is long time since I was doing something with iptables on linux. But you need something like this:

- On FortiGate create static route for 10.1.1.10 and gateway should be your PC 192.168.1.80

- On FortiGate then create VIP with port-forwarding that you need and use it firewall policy

- Now on linux you just need to add iptable entry that will forward this traffic from any source, on port 10000/UDP to the correct PC.