This post was written 5 years ago.
Wed, 02 Nov 2011
I was having a confusing issue where after moving an ubuntu virtualbox virtual machine I was losing the virtual network adapters (i'm running one on NAT so the machine can access the internet via the host and one host-only so I can network between host and guest). After a bit of head scratching, I realised this was because the way I was "moving" a machine was by copying the hard disk image and creating a new machine. This means that the MAC addresses were getting reset. If I went into the virtualbox machine settings and changed these to the same mac addresses as were being used on the vm before it was moved, the network interfaces reappeared. I guess that's why I should be moving the machines with the config file too..
This post was written 5 years ago, which in internet time is really, really old. This means that what is written above, and the links contained within, may now be obsolete, inaccurate or wildly out of context, so please bear that in mind :)