ssh setup for Ubuntu 18 on VirtualBox on macOS

gistfile1.txt

My configuration to run Ubuntu on VirtualBox on macOS with both NAT and host-only network interfaces.

Overview
========
The Ubuntu guest has two network interfaces: a primary NAT interface to enable it to reach
the Internet (so things like apt will work) and a second, host-only interface to support SSH
from the macOS host.

Setup Steps
===========
1. Install Ubuntu 18 on VirtualBox with the default NAT network config

2. Shut down the Ubuntu VM

3. Create a host-only network on the macOS host:
     VBoxManage hostonlyif create
   This will create a network called vboxnet0.

4. View the new host-only network’s configuration:
     VBoxManage list -l hostonlyifs
   The output will look something like this:
     Name:            vboxnet0
     GUID:            0000-0000-0000-0000-0000
     DHCP:            Disabled
     IPAddress:       192.168.56.1
     NetworkMask:     255.255.255.0
     IPV6Address:     
     IPV6NetworkMaskPrefixLength: 0
     HardwareAddress: 00:00:00:00:00:00
     MediumType:      Ethernet
     Wireless:        No
     Status:          Up
     VBoxNetworkName: HostInterfaceNetworking-vboxnet0
   In this example, based on the IPAddress and NetworkMask values, the
   host-only network is 192.168.56.0/24.

5. In the VirtualBox GUI, select the Ubuntu VM, click Settings, then Network,
   then “Adapter 2." 6. Click “Enable Network Adapter” and select “Host-only Adapter”
   in the “Attached to” dropdown. Choose “vboxnet0” in the “Name” dropdown. Click OK.

6. In the VirtualBox GUI, start the Ubuntu guest.

7. Log into the Ubuntu guest and create a file /etc/netplan/00-static-ip.yaml containing:
     network:
       version: 2
       renderer: networkd
       ethernets:
         enp0s8:
           dhcp4: no
           addresses: [192.168.56.99/24]
           gateway4: 192.168.56.1
           nameservers:
             addresses: [127.0.0.53]
   In this example, 192.168.56.99 is the IP address of the Ubuntu guest on the
   host-local network.

8. On the Ubuntu guest,
     sudo netplan --debug apply
     ifconfig
   The output of ifconfig should show that the enp0s8 interface now has IPv4
   address 192.168.56.99.

9. Reboot the Ubuntu VM and verify that the interface still has that address.

10. From the macOS host, you can now ssh to 192.168.56.99 to reach the Ubuntu guest.