Internet works perfectly on host (Ubuntu 13.04, 32 bit, fully updated) but cannot connect to internet on guest Windows 7 (under Virtualbox 4.2). Have tried NAT and Bridge Network - none worked. I had internet connection in the guest OS a couple of months ago, but I haven't tried the virtualbox since and now it's gone for some reason. I would be grateful if someone could help me re-connect the windows OS back online (without the need to format my computer or to uninstall and re-install the guest OS). Thanks!
I was having the same problem on Ubuntu 12.10 64bit using Virtualbox 4.2.22. Here are the steps I took to solve my problem:
At that point you should be able to start a web browser in your VM and get a connection. This video provided the information I listed above even though it was used on a Windows 7 host with a Windows Server guest.
Here is an image showing an example of the settings you need (taken from this answer):
For wireless to work, in my machines anyway, the WiFi MAC address in Settings must match the hardware, and wlan0 must be selected (when host Internet comes through wireless).
After gaining much more experience with this, I find:
Here's a quick HowTo:
First click your network icon and select Connection Information.
On the Hardware Address line, copy the MAC address (the six digit-pairs separated by colons).
Paste in a neutral location such as a text editor, where the colons can be edited out (remove them). Copy the rendered 12 characters remaining.
Note: Attempts to paste the MAC with the colons still present will fail.
With the latest VirtualBox (VBox) available from *buntu repos, v4.1.12 at this writing:
In VBox, with the VM selected, click Settings. Click Network and on that page, typically under the Adapter 1 tab, click Advanced.
Click the dropdown at Attached to: and select Bridged Adapter. Highlight the 'Mac Address' data and delete it. Paste the true MAC address copied above.
Check parameters are set as follows, in order from top-to-bottom:
Note that in the VM window, for Win7 at least, the WiFi symbol appears different from what it is in native mode. But WiFi is running nonetheless.