Category: VirtualBox

1. Install the needed packages to create kernel modules:

   sudo apt-get install dkms build-essential linux-headers-generic 

2. Press the Host+ D key combination or click on the Devices menu and choose the Install Guest Additions… option.
   
3. Mount the Guest Additions iso CD image:

   sudo mount -t iso9660 /dev/cdrom /media/cdrom

   mount: block device /dev/sr0 is write-protected, mounting read-only

4. Run the installation script

   sudo /media/cdrom/VBoxLinuxAdditions.run

5. Restart the guest machine.

As stated in the VirtualBox user manual, section 9.10.1 Configuring the address of a NAT network interface

In NAT mode, the guest network interface is assigned to the IPv4 range 10.0.x.0/24 by default where x corresponds to the instance of the NAT interface +2. So x is 2 when there is only one NAT instance active. In that case the guest is assigned to the address 10.0.2.15, the gateway is set to 10.0.2.2 and the name server can be found at 10.0.2.3.

This means that for Ubuntu, the /etc/network/interfaces entry for the network card settings are something as below:

iface <interface> inet static
    address <static IP> (e.g. 10.0.2.7)
    netmask 255.255.255.0
    network 10.0.2.0
    broadcast 10.0.2.255
    gateway 10.0.2.2

Also, add the following nameserver entry to /etc/resolv.conf

nameserver 10.0.2.3

Error message on boot
piix4_smbus 0000:00:07.0: SMBus base address uninitialized - upgrade BIOS or use force_addr=0xaddr

Error is caused by Ubuntu trying to load the smbus module which doesn’t exists in VirtualBox guest. It doesn’t seem to affect the function of the guest machine, but it’s kind of disconcerting having that error every time the machine starts up.

See if the i2c_piix4 module is indeed loaded with the command
lsmod | grep i2c_piix4

Blacklist the loading of the i2c_piix4 module by adding it in
/etc/modprobe.d/blacklist.conf.
sudo nano /etc/modprobe.d/blacklist.conf
and add

blacklist i2c_piix4

at the end of the file.

Update the initramfs with the command
update-initramfs -u -k all

The prompt will return something like
update-initramfs: Generating /boot/initrd.img-2.6.35-22-server