When you clone a VirtualBox machine in order to create a new virtual machine (as opposed to creating a back up of an existing machine) then you must check Reinitialize the MAC address of all network cards and use the Full clone type to make sure that the original and the clone don’t share any resources. After booting the new (freshly) cloned machine you will notice that all the network interfaces are down. Trying to raise them gives you the following:

[root@myhost ~]# ifup eth0 Device eth0 does not seem to be present, delaying initialization. [root@myhost ~]# ifup eth1 /sbin/ifup: configuration for eth1 not found. Usage: ifup <device name>

When Linux boots the clone image for the first time it sees the new MAC address. It compares it with the MAC address it has saved for eth0 and realises that they are different. In order to avoid a conflict (in case the old network card comes back), Linux creates a new interface called eth1. We are running VirtualBox (2.4.6) and don’t have network cards in the virtual machine. We just want it to be the same as the original machine without a lot of faff.

1. Edit the NIC cache:

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

2. Delete the line where NAME="eth0″
3. Find the line with NAME="eth1″ and change eth1 to eth0
4. Save file
5. Edit the new interface file:

   vi /etc/sysconfig/network-scripts/ifcfg-eth0

6. Strip out everything but the bare minimum:

   DEVICE="eth0″ BOOTPROTO="dhcp” ONBOOT="yes”

7. Save file, then reboot:

   reboot

The virtual machine will come back with eth0 raised and a brand new IP address. If I didn’t know any better I’d say someone is trying to recreate the behaviour that Windows has if you clone it. Each clone of a windows system remembers all the MAC addresses and names of previous NICs but what it means is that when you clone a system and update the drivers then all your names change back to the default plus one. for example if you rename your “Local Area Connection” to “outbound-if” and clone the system when it boots up on a different host with a slightly different firmware revision or different NIC then when the cloned system boots up, “outbound-if” will not be there “Local Area Connection 2″ will be there instead. You can’t change the device name to “outbound-if” because that name is taken by the system. There is no way to change this. I think the idea is that those settings are tied to the MAC address (hardware). So when the hardware changes you get a default configuration as standard. In my experience I’ve never had to add extra settings and my hardware changes have always been like-for-like. It has always been a nightmare that has taken ages to fix.