I installed the latest Ubuntu updates this morning, May 14, 2016 on two installations hosted by VirtualBox (4.3.28 on one machine and 5.0.20 on a second machine). After the Ubuntu update, the two machines will not connect to the internet.
Typing ifconfig on the two machines only provides one interface: 127.0.0.1.
Both of these machines were able to connect to the internet immediately before the Ubuntu upgrade.
I have checked a third Ubuntu installation on one of the hosts (4.3.28) and it is still able to connect to the internet. This third installation has not been updated to the latest Ubuntu updates.
Because VirtualBox and the third, non-upgraded Ubuntu installation are still working, it appears that the Ubuntu installation did something to affect network connectivity.
Attempting to start Firefox leads to:
Server not found Firefox can't find the server at start.ubuntu.com
Mail is also down.
This could be nasty if the upgrade is cutting the installs off from the internet!
