Cable Problems

Cable Problems

Unplugged or loose cables are the most common problem that causes Ethernet-related error messages. For example:

unix: <ethernet_device>: no carrier: check Ethernet cable

This message means that the carrier was not detected when attempting to transmit. One recommendation is

Check to see if the Ethernet cable is unplugged from the back of the machine. For detailed instructions on connecting the cable, see your owner's guide. You do not need to shut down the system to connect or disconnect the cable. If you re-connected the cable, test the network connection.

After determining that the transceiver cable is plugged into the back of the machine and also into the transceiver box, look for other possible reasons for failure.

Check the machine's transceiver.
Check the transceiver cable, and try swapping it out with one that is working on another machine.
Check for a problem with a 10baseT hub.
If you try all the troubleshooting techniques and you still cannot access the network, contact your service provider; the network itself may be temporarily out of order.

For more information on this error, see the reference page for ethernet(7).