Network interface missing in ubuntu after changing MAC address

Question

Hi I'm using Ubuntu Server on my VirtualBox. But I changed the MAC address of the NIC from virtual box settings. But now I cannot find the interface when I enter ifconfig. What should I do?

Solution

have you ran ifconfig -a ?

ubuntu and debian these days use udev to persistently assign the same nic the same device name. This works great except for when it doesn't do what you want it to do.

justin@media:~$ cat /etc/udev/rules.d/70-persistent-net.rules 
...
# PCI device 0x8086:0x100e (e1000)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:08:74:f2:83:e2", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"

if you run that on your VM you will most likely see two lines, one for eth0 and one for eth1. the easy way to fix it is to delete the eth0 line, and change the remaining eth1 to eth0.

Comments

[Tgr]

For Google's sake, the error you get when trying to ifup the interface is ERROR while getting interface flags: No such device.

[Tgr]

Or you can just delete the whole file and reboot, it will be recreated.