eth0 vs em1

[jim_deadlock]

In the past my network connection has always been called eth0, but since I did a fresh install of 13.04 it's been called em1. It works perfectly fine but I'm just wondering if there's any significant difference between 'eth' and 'em'? Or is it just an arbitrary name?

[grahammechanical]

What I see is Wired Connection 1. Which I think is more helpful for a the ordinary user. I do believe that it is possible to edit that label. That is all it is realy, a label.

Regards.

[jim_deadlock]

Yes I know about the 'Wired 1' label but what I'm talking about is what shows when you do:

ifconfig

[mikeym]

Not sure why it would be in Ubuntu but http://fedoraproject.org/wiki/Featur...rkDeviceNaming

[jim_deadlock]

OK so it's just a new port naming convention and not something that should concern me

[mikeym]

It look like you could try adding "biosdevname=0" to your kernel command line in /etc/default/grub and updating with update-grub2 to restore it back to eth0.

[jim_deadlock]

Yes that worked exactly as you described!

[jim_deadlock]

So I read man biosdevname and it seems that eth supports hotplugging but em (default policy) does not, so it's better to force eth as I've just done right?

[mikeym]

Sorry that's the limit of my knowledge (except to say that there has obviously been a choice to switch to em1 for a reason, I'm just not sure what - possibly consistent naming of network cards). Perhaps someone in the know could answer.

Anyway I also found this: http://www.cyberciti.biz/faq/howto-l...ed-using-udev/

Which looks like another way of renaming em1 to whatever you like. I'm not sure how it would work in practice because my copy of the suggested file /etc/udev/rules.d/70-persistent-net.rules has a header that implies that it gets overwritten from somewhere.

# This file was automatically generated by the /lib/udev/write_net_rules
# program, run by the persistent-net-generator.rules rules file.
#
# You can modify it, as long as you keep each rule on a single
# line, and change only the value of the NAME= key.

# PCI device 0x1969:/sys/devices/pci0000:00/0000:00:1c.3/0000:01:00.0 (atl1c)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="f4:6d:04:2a:6d:3e", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"

# PCI device 0x168c:/sys/devices/pci0000:00/0000:00:1c.1/0000:02:00.0 (ath9k)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="e0:b9:a5:5c:7f:85", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="wlan*", NAME="wlan0"