No Ethernet with RTL8125

Support Network
21

Then from software perspective all looks good and maybe something is broken physically.
As a last resort you could try: ethtool -s eno1 speed 100
Reason: 100Mbps just needs two wire pairs, whilst 1Gbps needs all four. Means if one wire needed for 1Gbps has a problem, 100Mbps might still work.

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22

As a last resort you could try: ethtool -s eno1 speed 100

That did nothing… until I pulled the cable out and plugged it in again. Now it finds the connection :partying_face:
Thank you so much!

Is there anything I can set so I don’t have ot run that command on every boot?

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Usually the ethtool speed command triggers an auto-negotiation and re-plugging the cable isn’t needed. This leaves one question: What is your link partner, and has it auto-negotiation enabled? Not that your link partner is fixed at 100Mbps. Output of ethtool eno1 may help.

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On the other end of the cable the router is directly connected. Auto-negotiation IIRC didn’t work correctly with my old PC (but it does for everything else in the house) or I just had a slower connection, so it was actually disabled in the UI.
However back then it definitely did show the connection, here it didn’t even recognize there was a cable plugged in (no LED blinking on the port or anything)

$ ethtool eno1
Settings for eno1:
        Supported ports: [ TP    MII ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
                                2500baseT/Full
        Supported pause frame use: Symmetric Receive-only
        Supports auto-negotiation: Yes
        Supported FEC modes: Not reported
        Advertised link modes:  100baseT/Half 100baseT/Full
        Advertised pause frame use: Symmetric Receive-only
        Advertised auto-negotiation: No
        Advertised FEC modes: Not reported
        Speed: 100Mb/s
        Duplex: Full
        Auto-negotiation: off
        master-slave cfg: preferred slave
        master-slave status: slave
        Port: MII
        PHYAD: 0
        Transceiver: external
netlink error: Operation not permitted
        Link detected: yes
25

Maybe the old PC supported max. 100Mbps. Best should be to re-enable auto-negotiation in your router and use the USB network adapter with the old PC if needed. With auto-negotiation in the router re-enabled, do you have 1Gbps after reboot of your system?

Everything is good for something: You got an idea how to analyze network problems. So you don’t have to believe any longer the people who immediately say (w/o having seen any log): the driver is crap.

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My router apparently doesn’t support auto-negotiation, I can only switch between 100Mbit and 1Gbit.
Edit: after setting it to 1Gbit however the connection works automatically :slight_smile:

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