When cloning an Ubuntu VMware virtual machine, eth0 goes missing. Fix the problem by deleting

/etc/udev/rule.d/70-persistent-net.rules

and rebooting.

I ran into an annoyance trying to clone some Ubuntu LAMP virtual machines that I was using for website development. Every time I cloned the virtual machine,

eth0

would go missing, and

ifconfig

would show only the loopback device, lo.

It turns out that when you clone a VMware virtual machine, the cloned virtual machine’s network interface gets a new MAC address (which, of course, it must to work on the same LAN). But Ubuntu, and many other Linux distributions, cache the old MAC address in a configuration file.

In Ubuntu, the file is

/etc/udev/rules.d/70-persistent-net.rules

. After cloning, it will contain a reference to the old network interface as

eth0

:

The easiest way to fix this problem is to simply delete the file. Ubuntu will regenerate it properly the next time it boots up.

 $ sudo rm /etc/udev/rules.d/70-persistent-net.rules 

After deleting the file, you need to reboot. If you can't reboot server please read Manually trigger creation.

After rebooting,

ifconfig

should show

eth0

and everything should just work.

If you’re feeling less adventurous, you can rename the file to *.old so that you can restore it if something doesn’t work:

 $ sudo mv /etc/udev/rules.d/70-persistent-net.rules /etc/udev/rules.d/70-persistent-net.rules.old 

You can also edit the file to remove the old reference to

eth0

, and rename the new

eth1

reference to

eth0

. But deleting the file and rebooting seems more convenient.

The relevant filename is slightly different in other Linux distributions. For example, in Debian, the filename is

/etc/udev/rules.d/z25_persistent-net.rules

.