I have an unused Raspberry Pi 4 (2GB model) lying around and I would like to install OpenWRT on it and use it as a router. I get Internet from DSL so I can’t hook it up on the Raspberry Pi directly, I need to plug an Ethernet cable coming from my actual router to the Pi.
I am no expert on networking, so please forgive me if I say something that is wrong. I want the WAN coming in from the router from the Pi’s Ethernet port, and the LAN coming out as Wi-Fi. I may also stick an additional Ethernet adapter to it in the future. I have tried doing this many times and have failed. So, could anyone explain to me how could I do this?
Also, what are VLANs, what are their uses and if I wanted one, how could I setup it in OpenWRT?
Thanks in advance.
If you want to use the PI as a router you’ll probably end up with a double NAT situation which isn’t ideal but may work well enough. In terms of wifi performance, I wouldn’t expect a Pi to be particularly good here so I’m not sure this even worth it unless it’s just a budget issue and you don’t have any other options.
In terms of your problem, you should be able to assign the Pi ethernet port to the default WAN and WAN6 networks. As for wifi, the Pi adapter needs to have support for AP mode, and looking around it doesn’t seem clear if the built in wifi adapter supports that or not (most people using the Pi are using it purely as a router and not a wireless AP). If not, you’d need a USB wifi adapter that supports AP mode. You might want to get that additional ethernet adapter too for testing/debugging and it will allow you to add a dedicated wireless AP.
Just don’t do NAT on the Pi then…