Difference between NAT Bridge and Host Only in VMware and VirtualBox

NAT, Bridge and Host Only are probably one of the features that people who are learning to use virtualization software like . do not understand VMware or VirtualBox. In this article, we will discuss the difference between NAT Bridge and Host Only.

Read also: Types of network topologies, their advantages and disadvantages

Difference between NAT Bridge and Host Only

In general, there are three main types or modes of virtual networks: NAT, Bridge, and Host-Only. VirtualBox supports many other software such as intranet, generic driver, etc., but we will only discuss the three main types.


nat Network address translation is the simplest way to access the external network from a virtual machine. Normally, it does not require any configuration on the host network and the guest system. This is the default network mode in VirtualBox or VMware.

When a virtual machine has NAT enabled, it will act as a real computer connected to the Internet via a router. A “router,” in this case, is a VirtualBox or VMware network device, which assigns traffic to the virtual machine transparently. In VirtualBox, this router is placed between each virtual machine and the host. This separation maximizes security because by default virtual machines cannot talk to each other.

The disadvantage of NAT mode is that, like a private network behind a router, virtual machines are not visible and cannot be accessed from the external Internet. You can’t run server This way unless you set up port forwarding.

The network frames sent by the guest operating system are received by the NAT virtual machine, which extracts the TCP/IP data and sends it back using the host operating system. For applications on the host, or for other computers on the same network as the host, it is likely that data will be sent by VirtualBox or VMware applications on the host, using the host’s IP address. The virtual machine listens for responses to sent packets, returns the packets and sends them back to guest machines on their own network.

The virtual machine receives the network address and configures it on the private network from a DHCP server built into VirtualBox or VMware. The IP address assigned to the virtual machine is usually located on a completely different network than the host. Since more than one card of a virtual machine can be set to use NAT, the first network card connects to the private network, the second network card connects to network and so on.


bridge A type of network that uses device drivers on your host system that filter data from the physical network adapter. Therefore this driver is called a “network filter” driver. This allows VirtualBox or VMware to intercept data from the physical network and inject data into it, effectively creating new network interfaces in the software.

When a guest uses a connected interface, it looks at the host system as if the guest is physically connected to the interface using a network cable. The host can send data to the guest through that interface and receive data from it. This means that you can manage routing or connectivity between guests and your entire network. For this to work, VirtualBox or VMware needs a device driver on your host system.

host only

host only Networking is another network mode that has been added in virtual machines. It can be thought of as a combination of internal and bridge networking modes, as with bridge networks, virtual machines can talk to each other and hosts as if they were connected via a physical Ethernet switch. Similarly, as with internal networks, no physical network interfaces are required, and virtual machines cannot talk to networks outside of hosts because they are not connected to physical network interfaces.

When using a host-only network, VirtualBox or VMware creates a new interface on the host which then appears next to the current network interface. In other words, while in a bridge network, the existing physical interface is used to attach virtual machines, with only a host network, a new “loopback” interface is created on the host. And while there is an internal network, the traffic between virtual machines cannot be seen, the traffic can be intercepted on the “loopback” interface on the host.

Host-only networks are especially useful for preconfigured virtual machines, where many virtual machines are shipped together and designed to work together. For example, one virtual machine may contain a web server and the second a database, and because their purpose is to talk to each other, the tool can direct VirtualBox or VMware to set up a host-only network for both. The second network (the bridge) will then connect the web server to the outside world to serve the data, but the outside world cannot connect to the database.


This is the difference between NAT Bridge and Host Only. These three main types of networks are available in most virtualization software.

nat: Just like your home network with a wireless router, virtual machines will be assigned to separate subnets, such as Host computer and virtual machines your virtual machine can access the external network like your host, but there is no external access to your virtual machine directly.

bridge: Your virtual machine will be on the same network as your host, if the host’s IP address is And the IP of the virtual machine is It can be accessed from all computers on your host network.

Host only: The virtual machine will be assigned a single IP address, but it can only be accessed through the box the virtual machine is running on and no other computer can access it.

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