Ubuntu 17.10 host, Virtualbox 5.1.34_Ubuntu r121010.
In Virtualbox I have a couple guest systems – Windows 10, Linux Mint, Fedora – that had been working just fine, they had internet access. They all were set up with the NAT attachment.
Yesterday, for some reason I cannot figure out, they all lost internet access.
When I experimented and change the attachment setting from NAT to Bridged, they all again had internet access.
How can I figure out what the problem is with the NAT attachment setting?