I am running Ubuntu Linux via VirtualBox as a guest on top of a Win 7 Home Premium host. Everything was fine until a few days ago when my Internet connectivity started failing in Ubuntu. The default network connection is NAT (Network Address Translation). Under it, the problem is thus: I have Internet connectivity in Ubuntu for about 30 seconds, then it fails. When I change the network connection to "Bridged Adapter", this problem goes away, i.e., my Internet connection inside Ubuntu remains stable.
Also, for some reason, on my host (Win 7), my wireless connectivity bar (at the bottom right of the desktop) states that I have Internet access, but I am on an "unidentified network- no network access" which is strange since I am connecting via my laptop to my home router, as I've always done. I thought this might have had something to do with my Norton AntiVirus expiring a few days ago, but I just renewed it, and the problem remains. Does anyone have an idea about why NAT causes my Ubuntu Linux guest to drop out of Internet connectivity within 30 seconds but not so with "Bridged Adapter" networking? Thank you.