Use eth1 as uplink instead of eth0

Installing and Using OpenWrt Network and Wireless Configuration
1

This is my second day using OpenWrt. I am extremely impressed. I was trying to configure my Raspberry Pi 4B to work as a router, and I was getting nowhere. Now, I'm definitely getting closer.

Here's what I would like to get in the end:

  • The uplink will be connected via eth1. That's a USB-to-Ethernet adapter. My ISP gives me a direct Ethernet connection to the Internet. No router necessary.
  • I will eventually connect eth0 to my old router in bridge mode, so that I can use the extra Ethernet ports and the router's Wi-Fi access point abilities.
  • In time, I'll install things like my own customized DNS, Kubernetes authentication, and more on the router itself.

For now, I got the router/Raspberry Pi to get a regular connection to the Internet via eth0. It took some tweaking. I don't remember everything I did, but getting the USB adapter to work, the proper package installed, a custom name server address in the configuration, etc. were all fascinating problems.

But now, I think I've really found a bump in the road. If I connect my Ethernet cable through the USB adapter (eth1) I can connect to the router, but the router has no awareness whatsoever of the Internet. I can't even successfully ping 8.8.8.8. What I did was try to copy the settings of eth0 to eth1. I'm close but, obviously, some differences remain.

To create the bridge-wan device, I had to manually modify /etc/config/networks. The addresses 192.168.1.140 and 192.168.1.141 are because my current router is at 192.168.1.1.

As a new user, I cannot post more than one image and eight links, so I had to improvise.

The list of interfaces:

The two interfaces:

The firewall settings:

The two devices:
pasteboard dot co slash UJq1MBPXTLfK.png
pasteboard dot co slash knMUYN9r3c4Q.png

The bridge VLAN filtering. I have no idea how to set eth1 to have one of those. On eth0, if I do a mouseover on the "1000FD" tag, it says: "Connected, 1000 MBit/s, full-duplex."

In the general firewall settings:

Currently, these are the problems I am stuck with, all of the following work when the Ethernet cable is connected to eth0 but not when it's connected to eth1:

  • accessing the web interface
  • successfully pinging the address (ending in 140 or 141 depending on the device)
  • connecting via ssh to the address

As far as I can tell, everything else is identical for the two devices. Did I overlook something completely obvious?

2

Reset, swap eth1 and eth0 in /etc/config/network.

3

Okay. I'll try that. But I'd still like to know what causes my current state to be configured the way it is. Just to understand.

4

Having the same subnet on wan and lan side breaks routing, if you want to use the device as router.

5

I'll look into that. Thanks!

6

I have a bunch of old setup threads on this topic, just look up pi4 .

Basically if you are hooked up to a monitor, reset, swap eth0 and eth 1 right off the bat, hook up internet to the onboard which is now wan, then do opkg update and opkg install kmodxxxx depending on what usb you got, then you’ll have the driver for the usb, then you can swap eth0 and 1 back to default and boom you’re up