In VirtualBox, how do I set up host-only virtual machines that can access the Internet?

Question

In setting up virtual machines with VirtualBox, I often want the following characteristics

• VM has a static IP
• host can access VM without port forwarding
• VM can access the internet
• I can move my laptop from network to network (e.g. from home to office to coffee shop) without worrying about securing or reconfiguring the VM

None of the VirtualBox network connection methods satisfies these requirements on their own.

• NAT
  Requires port forwarding if you want to connect to the VM from the host.

• Host-only
  The VM can not access the internet unless the host is a router.

• Bridged
  Exposes the VM to the network; not portable.

Answer 1

I can get the setup I want by setting up two adapters on the vm.

VirtualBox 4.2.12
Ubuntu 12.04 guest

In VirtualBox > Preferences > Network, set up a host-only network.

Mine is called vboxnet0, it is manually configured:
ip 192.168.56.1
netmask 255.255.255.0
no dhcp

Then, in the network settings for the virtual machine, set up two adapters:

Adapter 1
host only, vboxnet0

Adapter2
NAT

Boot the virtual machine and log in through the console VirtualBox provides.

Run this to see your adapters:

ls /sys/class/net

In my case the adapters were named eth1 and eth2 (and lo, the loopback interface).

Then, edit your network configuration.

sudoedit /etc/network/interfaces


# The loopback network interface
auto lo
iface lo inet loopback

# Host-only interface
auto eth1
iface eth1 inet static
        address         192.168.56.20
        netmask         255.255.255.0
        network         192.168.56.0
        broadcast       192.168.56.255

# NAT interface
auto eth2
iface eth2 inet dhcp

Note that eth1 has no default gateway specified. eth2 will get a default gateway from dhcp.

---

Update March 2018

See this answer from @Hugo14453 for an updated version that works with Ubuntu 17.10 and newer.

Answer 2

Network configuration has changed in Ubuntu 17.10.1. You now use the netplan config.

I followed this guide here

As a migration of Christian's answer, do the following:

Create a new config file inside of /etc/netplan to hold your host-only adapter config.

e.g sudo nano /etc/netplan/02-netcfg.yaml

Enter the following to configure a static IP of 192.168.56.12 where enp0s3 is the name of your host-only adapter.

network:
    version: 2
    renderer: networkd
    ethernets:
        enp0s3:
            addresses:
                - 192.168.56.12/24
            dhcp4: no

Then run the following two commands:

sudo netplan generate
sudo netplan apply

NAT should work without configuration, run ifconfig to see the result:

enp0s3: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.56.12  netmask 255.255.255.0  broadcast 192.168.56.255
        inet6 fe80::a00:27ff:fe06:6cdd  prefixlen 64  scopeid 0x20<link>
        ether 08:00:27:06:6c:dd  txqueuelen 1000  (Ethernet)
        RX packets 252  bytes 23076 (23.0 KB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 208  bytes 30015 (30.0 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

enp0s8: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 10.0.3.15  netmask 255.255.255.0  broadcast 10.0.3.255
        inet6 fe80::a00:27ff:fe4d:a6b8  prefixlen 64  scopeid 0x20<link>
        ether 08:00:27:4d:a6:b8  txqueuelen 1000  (Ethernet)
        RX packets 95  bytes 94894 (94.8 KB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 85  bytes 7436 (7.4 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

Answer 3

I could solve my problem with a mix of Christian Long solution. I added 2 adapters:

Adapter 1 - NAT

Adapter 2 - host only, vboxnet0

The only diference was in VM's interfaces file:

sudoedit /etc/network/interfaces

# The loopback network interface
auto lo
iface lo inet loopback
# NAT
auto eth0
iface eth0 inet dhcp
# Host only
auto eth1
iface eth1 inet dhcp

In VirtualBox Network config I left DHCP checked.

After a VM reboot everything worked fine.

Answer 4

There is another simple way that we don't need to create a new NAT adapter

1. On the host machine, please add the following iptables rules. This will forward packets through the host and on to the Internet:

   sudo iptables -A FORWARD -o eth0 -i vboxnet0 -s 192.168.56.0/24 -m conntrack --ctstate NEW -j ACCEPT 
   
   sudo iptables -A FORWARD -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
   
   sudo iptables -A POSTROUTING -t nat -j MASQUERADE
   

2. You will also need to enable IP forwarding on the host by issuing the following command:

   sudo sysctl -w net.ipv4.ip_forward=1
   

Answer 5

I Just added 2 adapters:

Adapter 1 host only, vboxnet0

Adapter2 NAT

And it works perfect, I can access the virtual machine from the host, and I have internet on the vm.

Answer 6

Yeah I had this problem it was a total pain! But I solved it by simply installing Squid Cache Proxy server on my physical PC, and that way - my host-only internet virtualbox PCs could connect to the internet !

I did a quick 3 minute guide for anyone who wants to know how it works.

Answer 7

In my case, I could not see the IP 192.168.250.1 on vboxnet0 (e.g. with "ip addr"), despite setting this in the host-only network settings in VirtualBox, until I created the file /etc/netplan/02-vbox.yaml containing

network:
    version: 2
    renderer: networkd
    ethernets:
        vboxnet0:
            addresses:
                - 192.168.250.1/24
            dhcp4: no

and ran "netplan generate && netplan apply"