A Default VirtualBox configuration does not allow direct host-> guest access, it's on some hidden VB-only NAT. You need to change the Network Interface type to Bridged or Host-only or something else to have access to the VM.
I haven't done it for some time, but in my memory it was neither a problem on OSX nor on Linux with VBox. Maybe try Vagrant? I don't remember, sorry. But ask around and you should find a super easy way to make this happen.