From your description, it seems you’re running a Dual-WAN setup with one RED interface in IPFire, where both WAN connections are within the same subnet. This is a little different from the typical configuration I had in mind, where two separate interfaces would be used.
In your scenario, you can assign a second IP address to your RED interface to create distinct routing paths for your two WAN connections. Here’s how it should be:
First, assign the second IP address to the RED interface:
ip addr add 192.168.1.10/24 dev red0
Next, create separate routing tables:
ip rule add from 192.168.1.9 table 1
ip rule add from 192.168.1.10 table 2
ip route add default via 192.168.1.1 dev red0 table 1
ip route add default via 192.168.1.2 dev red0 table 2
In this example, we have two routing tables: table 1 and table 2. The rules starting with ip rule add specify that if a packet originates from 192.168.1.9, it should use table 1 for routing, and if it originates from 192.168.1.10, it should use table 2. The default routes for each table are added using the ip route add default command.
This way, you can manage traffic from different IP addresses on the same interface independently, which is probably what you want to obtain with the dual-WAN setup like yours.
As a note, I’ve been using the language model ChatGPT-4 to answer to your question (btw, I am curious by nature and problems like this always draw my attention). If you learn how to prompt the AI model, you can also interact directly with the AI to gain further insights. Their answers cannot be taken at face value, but very often they point to the right direction and with the right follow-up you can fill the knowledge gap you need to have the right mental framework. Then, it’s just a matter of testing and refining your questions. If you get the wrong answer, it is because you asked the wrong question.
