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I have a Linux machine with two Ethernet cards both using the Intel e1000 driver. lspci reports different models of Ethernet cards, but I can't tell which is eth0 and which is eth1. Other than turning off the machine and reading the chips, how can I tell which model is eth0 and which is eth1?

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That's why I never used two of the same brand/model – OMG Ponies Nov 2 '10 at 21:32
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3 Answers

up vote 6 down vote

I haven't tried it myself, but try the ethtool command. With

ethtool -p eth0

you can get the LEDs on the card to blink. You can then easily identify which card is blinking.

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Check the manpage for details: linux.die.net/man/8/ethtool – socken23 Nov 2 '10 at 21:44
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up vote 4 down vote

Parse the output of ifconfig. It will give you the hardware MAC address that you can use to identify which card is which.

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Is there a mapping somewhere from lspci output to mac address? Unfortunately, I don't have the mac addresses written down. – User1 Nov 3 '10 at 3:53
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up vote 1 down vote

Connect only one of the interfaces to a switch then use the output of mii-diag, ethtool or mii-tool (depending on which is installed) to see which has a link. You'll then know which physical card is which interface. The output of dmesg should then help you work out which is which.

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