Here's my situation:

• an Ubuntu 12.04 Host running VirtualBox;
• two guest VMs running Ubuntu Server 12.04
• home network, so my Host pc has a wireless connection to the router of my ISP.

My problem is in one of the virtual machines: it has 3 NICs, one in NAT mode and the others in Host Only mode. My purpose is to use eth0 (NAT) for Internet access and eth1, eth2 (Host Only) for management of internal virtual network (eth1 uses a VBoxNet with this IP 192.168.69.254).

Whenever I try to $ping 8.8.8.8 I get Destination Host Unreachable.

While if I $ping 192.168.69.10, that is the IP of the other VM, it works.

I can't also ping my Host nor my router

My /etc/network/interfaces file is: auto lo iface lo inet loopback

auto eth0
iface eth0 inet dhcp

auto eth1
iface eth1 inet static
address 192.168.69.1
netmask 255.255.255.0

auto eth2
iface ifconfig $IFACE 0.0.0.0 up
up ip link set $IFACE promisc on
down ip link set $IFASE promisc off
down ifconfig $IFACE down

$route -n returns:

Destination   Gateway     Genmask        Flags Metric Ref Use Iface
0.0.0.0       10.0.2.2    0.0.0.0        UG    100    0   0   eth0
10.0.2.0       0.0.0.0    255.255.255.0  U       0    0   0   eth0 
192.168.69.0   0.0.0.0    255.255.255.0  U       0    0   0   eth1
192.168.100.0  0.0.0.0    255.255.255.0  U       0    0   0   virbr0

Forgetting for now what eth2 needs to do and its setup, why I can't go outside the Host box?

What can I do to help you helping me? :-)