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.
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 xbuntu 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 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 nevertheless.