When learning about virtualization software such as VMware or VirtualBox, there are three features that some people have difficulty understanding: NAT Bridge, Host-Only, and Bridged. In this article, I will discuss the difference between NAT Bridge and HOST settings to help you better understand them when using your own computer for testing purposes.
NAT is short for Network Address Translation which can also be written out in full form – Network Address Translator. The purpose of having a network address translator enabled on our system means all machines inside LAN (Local Area Network) do not need unique IPs while accessing the outside world via an internet connection through one port only e.g., Port 80 or UDP 443, etc. This helps us reduce costs by allowing more than 1 PC/Laptop.
Difference between NAT Bridge and Host-Only
Networking types in virtualization include NAT, Bridge, and Host-Only. VirtualBox supports many more such as Internal Network, Generic Driver, etc., but we will only discuss the three main ones here which are widely used.
In VirtualBox or VMware, NAT is the default network mode. When a virtual machine enables this network type, it will act like an Internet user connected to their router which maps traffic to them transparently.
The disadvantage of NAT mode is that virtual machines are invisible and unreachable from the outside internet. However, you can set up port forwarding to allow it in this case.
In VirtualBox, the router placed between each virtual machine and host maximizes security because by default they cannot talk to each other; however, you may need to set up port forwarding for access if so desired.
The NAT virtual machine extracts the TCP/IP data and sends it back using the host operating system. For applications on the guest, or to other computers on a private network as them, they are likely receiving packets from VirtualBox or VMware’s application running in their own OS for that respective computer. The guest listens for replies to sent packets before repackaging and sending them back out through its private network so only other machines can receive those packages while being routed by our server which is acting as an intermediary gateway between both networks communicating with each device respectively by translating this transmitted package into destination addresses of either endpoint involved in this communication session.
A virtual machine receives its network address and configuration from a DHCP server integrated into VirtualBox or VMware. The IP address assigned to the VM is usually on a completely different network than that of the host. Each card, in this case, has an option for NAT because more than one can be set up to use it; so naturally, they will go by private 10.10 networks: first at 10.10. Then the second would be something like 20.
How does it work?
A person is working on their laptop in the comfort of home and searches for directions to a favorite restaurant. The request reaches the router which changes its outgoing IP address from local private to public, otherwise known as changing your return service with anonymous mail (such as mailing something with no name). Then it forwards this information along through web servers across town but without receiving any packets back because they don’t know where that packet came from.
VirtualBox and VMware use a technology called bridged networking to pass data from your physical network adapter through the host operating system’s drivers. This allows VirtualBox or VMware to intercept traffic from that device, effectively creating new interfaces in software.
When a guest is bridged it will look to the host system as if they were physically connected through network cables. This means that you can manage routing or bridge between guests and your entire network. VirtualBox or VMware needs device drivers on your machine for this to work which allows them access into the operating system of each program.
Allowing virtual machines to communicate with each other and the host is similar to a bridge, but they are not connected via a physical network interface. This means that virtual machines cannot access networks outside of their hosts because they aren’t directly hooked up to physical interfaces.
By using a host-only network, VirtualBox or VMware creates an entirely new interface on the physical machine. It appears next to your existing interfaces like Ethernet and Wi-Fi. With this set up if you use bridge networking then traffic between virtual machines cannot be intercepted; however, with a host-only network, it’s possible for someone who has access to your computer (and is looking) to see what should be hidden from view because of that loopback interface!
Virtual machines are not only useful for virtualizing single computers. They can also be used to create a miniature network of two or more VMs that work together, called guest-only networks (no connectivity outside the host). For example, you could set up an environment with one VM running web services and another database server; this would make it difficult for outsiders to access your data because they cannot connect directly into the private network between these servers.
The internet has experienced explosive growth over the past few decades, and although there are 4 billion possible IP addresses using IPv4, only a fraction of that number is left. In addition to this shortage problem with available numbers for devices on the internet today adding up to more than 4 billion individual device addresses, many times even one person will own several electronic gadgets which require an address assigned individually for each gadget.
Networking can be pretty confusing when it comes to virtualization, but there are three main types of networks that will help you understand how your network works. NAT: just like in your home with a wireless router, the host computer and VM’s have their own subnets assigned. The IP address for our example would look something like 192.168-.1 from the perspective of a guest machine while Host 1 has an IP on .2 or even higher up depending on its number designation
So that’s the difference between Network Address Translation (NAT) Bridge and Host-Only Virtual Networks!