My host is an out-of-the-box Ubuntu 12.10 simply connected to Wifi.
I installed VirtualBox, and then a few Linux and Windows 7 Pro guests on it, all with default VirtualBox options (NAT).
I reboot them every day.
Yesterday all had network access.
PROBLEM: Today all the Windows guests says "No Internet access".
Linux guests still have network.
As an experiment, I created a new guest VM, installed Windows inside. Result: no network.
All Windows and Linux guests are out-of-the-box, I did no network tweaking whatsoever. Below is their VirtualBox-side network configuration just in case:
(2 years later: exact same problem happened, a VM that was working yesterday… same solution)
Best Answer
As John Siu tipped me, there is probably something wrong with the DNS server in my network.
The solution was to change the DNS from
Obtain DNS server address automatically
toUse the following DNS server addresses
, and entering Google's DNS service addresses, as seen in this screenshot: