After upgrading to 12.10 from 12.04 none of my virtualbox virtual machines can use NAT to access the network. I have tried vboxmanage modifyvm --natdnsproxy1 on and/or --natdnshostresolver1 on, but still doesn't work. What can I do to resolve this? I have also upgraded to Virtualbox 4.2.4 to attempt to resolve this issue.
I had the same problem, but without updating to 12.10: I already was in 12.10 last Wednesday, the last time I used the virtualmachine, but on Sunday I couldn't access the network from any virtual OS (tried both Windows 7 and Windows 8). Also tried to update from virtualbox 4.1 (bundled with ubuntu) with virtualbox 4.2 from the Oracle website, but nothing changed.
I guess an Ubuntu update broke something.
I've tried an answer from another thread and it does work
VBoxManage modifyvm "name" --natdnshostresolver1 on VBoxManage modifyvm "name" --natdnsproxy1 on
(PS: I couldn't add this as a comment to the original question, don't have enough reputation, but thought it could be useful)
One of the reasons it does not work directly from 12.10 is here https://www.virtualbox.org/ticket/10864
VirtualBoxes uses hosts /etc/resolv.conf file to map dns into its internal dhcp, thus blocking name resolution. In the waiting for a fix I had to manually setup dns servers on hosts resolv.conf file