First of all, install the DHCP server by using the sudo apt-get install isc-dhcp-server -y command, and then configure it by using the /etc/default/isc-dhcp-server file to use the network that you want for listening (such as eth0).

In the /etc/dhcp/dhcpd.conf file, you should configure some parameters such as the subnet and the address range. Then, restart it by using the following command:

sudo service isc-dhcp-server restart

After this, install the following packages that are necessary if you wish to set up the PXE environment:

sudo apt-get install apache2 tftpd-hpa inetutils-inetd

Now, it is time to configure the TFTP service. To do this, add the following two lines to the /etc/default/tftpd-hpa file:

RUN_DAEMON="yes"
OPTIONS="-l -s /var/lib/tftpboot"

Also, add the following line at the end of the /etc/inetd.conf file:

tftp    dgram   udp    wait    root    /usr/sbin/in.tftpd /usr/sbin/in.tftpd -s /var/lib/tftpboot

Then, reboot the service using the sudo /etc/init.d/tftpd-hpa restart command.

Now, we need to copy the installation files to the PXE server. In our example, I used the ISO image that I have in my home directory. First of all, mount it by using the following command:

sudo mount loop /home/abdelmonam/ubuntu-15.04-server-amd64.iso /mnt

Then, copy the required files to the server by using the following commands:

cd /mnt
sudo cp -fr install/netboot/* /var/lib/tftpboot/
sudo mkdir /var/www/Ubuntu
sudo cp -fr /mnt/* /var/www/ubuntu/

After doing this, modify the /var/lib/tftpboot/pxelinux.cfg/default PXE config file by adding the following lines at the end:

label linux
kernel ubuntu-installer/amd64/linux
append ks=http://192.168.1.1/ks.cfg vga=normal initrd=ubuntu-installer/amd64/initrd.gz
ramdisk_size=16432 root=/dev/rd/0 rw  --

Be careful when adding the IP address.

The last step required to set up the PXE server is to add the following lines at the end of the /etc/dhcp/dhcpd.conf file:

allow booting;
allow bootp;
option option-128 code 128 = string;
option option-129 code 129 = text;
next-server 192.168.1.1;
filename "pxelinux.0";

Then, reboot the DHCP server by using the following command:

sudo service isc-dhcp-server restart

Create the virtual machine with the characteristics that you want via the virtualbox manager.

Then, go to the Settings of the machine and select the System tab. In the Boot Order part, deselect all options and select Network, as shown in the following screenshot:

Select the Network tab and configure the network adaptor to act as a bridge.

Finally, start your VM. You will see the following interface: