From the guest machine I could access the internet and access the host machine, but I could not ping or access the guest machine from the host. Turns out there is a network setting that needs to be changed.
On the guests 'container' go to Devices > Network Adapters
Then change 'Attached to' from 'NAT' to 'Bridged Adapter'
at that point you should be good to go
- virtualbox forums: Host can't ping guest in Different OS ??