VMware Network Connection mode-detailed introduction and differences between bridging, NAT, and host-only mode. ZIW

January 10, 2017, Tuesday

VMware Network Connection mode-detailed introduction and differences between bridging, NAT, and host-only mode

In the process of creating a virtual machine using VMware Workstation ("VMware"), configuring the virtual machine's network connection is a very important link, and when we configure the network connection for the virtual machine, we can see several network connection modes as shown: bridging mode, NAT mode , host-only mode, and custom network connection mode. So what are the main uses of these kinds of network connection modes, and what are the differences between them?

AX, in order to better use virtual machines, it is necessary to understand the main purposes of these connection modes and the differences between them. Here, we take the following network connection as an example to do the relevant introduction.

In VMware, the network connectivity of virtual machines is implemented primarily by VMware-created virtual switches (also called virtual networks), and VMware can create multiple virtual networks as needed. On a host of Windows systems, VMware can create up to 20 virtual networks, each of which can connect any number of virtual machine network devices, and VMware can create up to 255 virtual networks on the host of a Linux system. However, each virtual network can only connect 32 virtual machine network devices.

VMware's virtual networks are named in the form of "vmnet+ numbers," such as VMnet0, VMnet1, VMnet2 ... And so on (on the host of the Linux system, the name of the virtual network is in lowercase, for example, Vmnet0).

When we install VMware, VMware automatically creates 1 virtual machine networks for each of the 3 network connection modes: VMnet0 (bridge mode), VMnet8 (NAT mode), VMnet1 (host mode only). In addition, we can create more virtual networks on our own as needed.

VMware Bridging mode

VMware bridging mode, that is, the virtual network adapter of the VM and the host's physical network adapter, the virtual network adapter in the virtual machine can be directly accessible to the external network through the physical network adapter in the host ( The local area network and the Internet, as shown in the example below). In short, it's like adding a new, stand-alone computer to the local area network as shown. As a result, virtual machines also occupy an IP address on the LAN and can be accessed from other terminals. The Bridging mode network connection supports both wired and wireless host network adapters. If you want to treat a virtual machine as a completely separate computer and allow it to communicate with other terminals, the bridge mode is usually the simplest way for a virtual machine to access the network.

VMware NAT Mode

NAT, which is the abbreviation for network address translation, is the translation of Web addresses . Nat mode is also the default network connection mode for VMware to create virtual machines. When using NAT mode network connections, VMware establishes a separate private network on the host to communicate with each other between the host and the virtual machine. The request data sent by the virtual machine to the external network "parcel" will be forwarded to the NAT network adapter with a "special token" and transmitted in the name of the host , the response data returned by the external network "package", is first received by the host, and then handed The NAT network adapter is identified and forwarded to the corresponding virtual machine according to the "special tag" , so the virtual machine does not have to have its own IP address in the external network. From the external network, the virtual machine and host are sharing an IP address, and by default, the external network terminal cannot access the virtual machine.

In addition, only one virtual network with a NAT mode is allowed on a single host. As a result, multiple virtual machines with NAT mode network connections on the same host can be accessed from each other.

As we mentioned earlier, the external network cannot access the virtual machine by default, but we can also implement port forwarding by manually modifying the NAT settings to forward the data sent by the external network to the host-specified port to the specified virtual machine. For example, we "establish" a site on the 80 port of the virtual machine, as long as we set up port forwarding, the host 88 port data forwarded to the virtual machine 80 port, you can let the external network through the host's 88 port access to the virtual machine 80 port on the site.

VMware Host-only mode

host-only mode, which is a more closed network connection mode than NAT mode, creates a private network that is fully contained in the host. Only the host-mode virtual network adapter is visible to the host and provides network connectivity between the virtual machine and the host system. Compared to NAT mode, host-only mode does not have NAT, so by default, virtual machines that use only host-mode network connections cannot connect to the Internet (install the appropriate routing or proxy software on the host Or, you can still have the virtual machine connected to the Internet or another network by using the Internet Connection Sharing feature on the host on the Windows system.

Multiple host-only virtual networks can be created on the same host, and if multiple virtual machines are in the same host-only mode network, they can communicate with each other , and if they are in a different host-only mode network, they cannot communicate with each other by default ( You can communicate with each other by setting up routers between them.

Customizing the network Connection Configuration

You can also create complex virtual networks with the virtual network connectivity components provided by WMware. Here we don't go into detail, you can refer to the official documentation and then create the virtual network with VMware's Virtual network editor.

The image says:

Bridge mode virtual machine, like a router "Civil Affairs bureau" there "on the account" of adults, have their own separate residential address, although and host live in the same compound, but at least there are accounts of people, can swagger directly and outside communication.

Nat mode virtual machine, is purely a Heihu account, the router "Civil Affairs Bureau" does not know that there is such a person, nature will not actively communicate with it. Even if the virtual machine occasionally to send the point of the letter to the host to be forwarded to the host in the name of the forwarding out, the host also specifically invited a NAT called the grandfather to specifically responsible for these virtual machine's letter, receiving letters.

Host-only virtual machine, purely a thorough bottom of the black slaves, not only have no account, router "Civil Affairs Bureau" do not know so people, but also by the main organs in the small black House, even the letter is not allowed outward.

Source: http://www.softown.cn/post/13.html

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VMware Network Connection mode-detailed introduction and differences between bridging, NAT, and host-only mode. ZIW