How To Determine Which Network Interface Belongs To Which PCIe Device

How To Determine Which Network Interface Belongs To Which PCIe Device

If you have physical access to the system, you can identify with 'ethtool -i' which will blink the NIC. How the NIC blinks depends on the model. The Mellanox cards have an orange light on the PCB that will blink.

~$ ethtool -p enp33s0


If you are remote, you can try to figure it out from the device number. This method involves getting the device number from ethtool and locating that device number in lspci


1.) Run ethtool -i against the interface to find the device number from the bus-info field.



~$ ethtool -i enp33s0
driver: mlx5_core
version: 3.0-1 (January 2015)
firmware-version: 12.22.1002
expansion-rom-version:
bus-info: 0000:21:00.0
supports-statistics: yes
supports-test: yes
supports-eeprom-access: no
supports-register-dump: no
supports-priv-flags: yes

2.) Use lspci to locate the device by device number.


~$ lspci -v|grep '21:'
21:00.0 Ethernet controller: Mellanox Technologies MT27700 Family [ConnectX-4]


You can do this process in reverse as well.


Here is a one-liner to get all the interfaces and run ethtool -i against them in a loop

  1. for i in `ip link show| grep -v link| grep -v 'lo:'| awk {'print $2'}| sed 's/://'`; do echo $i; ethtool -i $i; echo "#####" ;done




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