Once a guest machine is installed, the first step that everyone like to do is to configure the network for that machine.
The following are the different types of networking modes available to be configured for each network adapter
- Network Address Translation (NAT)
- Bridged Networking
- Internal networking
- Host-only networking
Network Address Translation
When a guest machine is set-up in this mode, then outside world will never be able to communicate with the Guest machine directly. When the guest machine send an IP packet to some remote machine, VirtualBox’s NAT Engine will receive the packet and extracts the TCP/IP segments, and change the IP address to the IP address of the HOST machine. So the outside world only see the IP address of the Host machine. When an reply is sent, then it will be received by the HOST machine and resend to the Guest Machine.
It is similar to connecting a physical machine in a network. Outside world can directly communicate with the Guest machine. When a guest is configured for Bridged Networking, then VirtualBox uses a device driver on the host system, which can intercept and inject data through the physical network adapter present in the HOST machine.
We can create more than one Guest machine, using VirtualBox. So if we want all the guest machine to communicate internally, then we can use this Internal Networking mode. Though we can use Bridged Networking also for this, Internal Networking is more secure.
In Bridged Networking, all the packets are sent/received from the physical network adapter in the HOST machine. If someone attaches a packet sniffer tool in the HOST, then all the communication will be captured. In case of Internal Networking, the communication between the Guest machines will be secure.
It is a hybrid of Bridged and Internal networking. In this mode, the Guest machine can talk to each other and also with the Host machine. It will look like, all machine ( including Host and Guest Machines ), are connected to a physical network switch. The guest machine cannot communicate with the outside world too, since they are not connected via a physical interface.
for more check this link : thegeekstuff.com/vmnetworking