eth0 stopped transmitting data on my RPi Router

userHead GabrielKlavans 2022-10-09 14:42:17 1469 Views3 Replies

I've been using my Raspberry Pi CM4 as a router using DFRobot's Router Carrier board for a while. However, after power cycling one day, the internet just completely cut out.


After days of troubleshooting, I've determined that the eth0 port simply does not transmit meaningful data anymore. In OpenWrt, if I swap the wan and lan interfaces so wan uses eth1 and lan uses eth0, I can get internet (from an upstream router, I assume also from the modem but it's impossible to test because:), but can no longer connect a computer to the router's lan using eth0.


This is perplexing since activity indicator lights consistent come on and blink when plugging into the seemingly broken eth0 port. I'm not sure what's gunking up the connection, but this issue has persisted through a complete wipe and clean install of OpenWrt.


Any thoughts?

2022-10-25 10:06:11

Hi! Thanks for your feedback. We will test this problem. If there is a solution, we will reply to you as soon as possible.

userHeadPic jenna
2022-10-24 01:41:34

So, I’ve truly eliminated the possibility that it’s a software issue, as I’ve gone through several clean installs with drive mods, to no avail.


tcpdumo says “That device is not up” when I tell it to listen to eth0, and I can’t seem to find further discussion on this error online, so I’m really stuck here. Gonna just hope it’s a hardware issue with the router carrier board and order a new one. If it’s a problem with my rpi, that will be a lot harder to replace..

userHeadPic GabrielKlavans
2022-10-09 14:52:05

To add, I didn't run any tests to see if any data at all could flow through eth0 (I potentially could have by plugging wan into an upstream router, then connecting to the raspberry pi router in the upstream router's lan, then running some cli commands) but I saw 0 packets transferred consistently on whatever interface was assigned to eth0, so I figured that was damning enough.

userHeadPic GabrielKlavans