I am trying to connect 2 linux machines via crossover cable. I think I have set them up correctly, but one thing befuddles me - my laptop says 'ethernet cable unplugged'. ip addr l shows interface is down. Both the laptop and the machine are manjaro (i.e. arch). I think that the cable must be at fault, because if it was correct crossover, then the ethernet socket lights should be on and cable should be detected, right? Or is there something I am missing completely? Thanks

  • The ethtool command can give you low level status of the link, eg sudo ethtool eth0 should have near the end of output the line: Link detected: yes. If at least one interface is a gigabit device it should do auto-detection of need for crossover so a straight cable could work. You can normally see the wires in the cable end plugs: check the colours are ok for crossover. – meuh Mar 31 '17 at 17:03
  • 1
    Cross over cables are not needed as much any more. Most NIC take care of that themselves, and I do not believe that a Gig NIC can use a cross over cable at all. – jc__ Mar 31 '17 at 18:09
  • I see, maybe that's the problem. Laptop is a year old but the computer box is maybe 10+ years old. Both work fine with a 10 mb switch though. – r0berts Mar 31 '17 at 18:56
  • Thanks for advice ethtool is very useful . Turned out to be bad cable. Crimped one myself and it works alright. – r0berts Apr 1 '17 at 13:18

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.