Virtual Machine can access internal network but not the internet

Set your Virtual machine to use NAT, I bet that takes care of your problem.

The problem was that my company uses a proxy server and I had to define it in the virtual machine. Thanks for the help though.

I also had this sort of problem. But In my case, Ubuntu 11.10 was on VirtualBox on Windows 7 Enterprise, and tightly secured corporate network. But the issue, I think, was on host side.

What I did, is as follows:
1. On VirtualBox's Network setting, choose "NAT", and check "Cable connected"
2. On host machine's network adapter settings, re-check that "VirtualBox Host-Only Network" has DHCP, all other settings are set to automatic.
3. On host machine's own "Local Area Connection", went to "Properties">>"Sharing", and check "Allow other network users ...". And "OK"
4. On virtual machine, Disconnect once by "Uncheck"ing "Enable Networking", then "check" again.

Bingo!, then Internet was working fine.