How do I find the mac address of a USB to ethernet adaptor?

[settingsun]

I'm learning to install a USB to ethernet adaptor to give my fedora laptop a second nic that can run https. I assume every nic needs its own configuration file in /etc/sysconfig/network-scripts.

When I plugged it into the laptop and used network manager, the manger created a ifcfg-eth2 file but gave it no mac address. I want to put the mac address into ifcfg-eth2 manually, or just make my own ifcfg-eth1.

I did a search and found an article that says the mac address is printed on the back of the device. There are 3 numbers on the back of my device. One starts with "S/N:", another starts with "H/W", but this is only 4 characters long, and another is on a barcode.

Does anyone know if one of these is the mac?

Btw, why would the network manager go from eth0 to eth2? Why skip eth1?

Thanks

[DBelton]

running the arp command as root user should give you the MAC address of your ethernet adapters.

[JEO]

The following command will display the mac address on the first line (HWaddr):

ifconfig eth2

As far as going from eth0 to eth2, have a look in the file /etc/udev/rules.d/70-persistent-net.rules. Each time a network card is plugged in it gets added to this file (mac address to ethX). Also I think wireless cards appear in the file (wlanX). You are allowed to edit this file to change it if you want. I believe the exceptions to being included in this file are for embedded cards (they get emX) and pci (they get names that start with p)

[settingsun]

Thanks to everyone for replying.

JEO - cat /etc/udev/rules/70-persistent-net.rules showed me the USB device with an ATTR{address}=="00:xx:xx:xx:xx:xx"


Is this the mac?


The name entry is: NAME="eth1"

That doesn't make sense, because the network manager shows it as eth2.

[JEO]

Yes the ATTR{address} is the same thing as the HWaddr or mac address.

[settingsun]

Thanks again -

I was typing another message as you were replying, so I'll type it again here:

The Name entry reads like this: NAME="eth1"

This is strange because network manager shows it as eth2.

[JEO]

NetworkManager might also be renaming the interface. I'm pretty sure if that is the case the renaming will show up in /var/log/messages each time NetworkManager sees the interface.

[settingsun]

Thanks very much for your help.