The following items are components of a virtual network:

Like a physical switch, a virtual switch lets you connect other networking components together. Virtual switches are created as needed by the GSX Server software, up to a total of ten switches on a Windows host or 100 switches on a Linux host. You can connect one or more virtual machines to a switch.

A few of the switches and the networks associated with them are, by default, used for special named configurations. The bridged network normally uses VMnet0. The host-only network uses VMnet1 by default. And the NAT network uses VMnet8 by default. The others available networks are simply named VMnet2, VMnet3, VMnet4, and so on.

You connect a virtual machine to a switch by selecting the virtual network adapter you want to connect in the virtual machine settings editor, then configuring it to use the desired virtual network.

The bridge lets you connect your virtual machine to the LAN used by your host computer. It connects the virtual network adapter in your virtual machine to the physical Ethernet adapter in your host computer.

The bridge is installed during GSX Server installation (on a Linux host, you must choose to make bridged networking available to your virtual machines). It is set up automatically when you create a new virtual machine using bridged networking.

Additional virtual bridges can be set up for use in custom configurations that require connections to more than one physical Ethernet adapter on the host computer.

The host virtual adapter is a virtual Ethernet adapter that appears to your host operating system as a VMware virtual Ethernet adapter on a Windows host and as a host-only interface on a Linux host. It allows you to communicate between your host computer and the virtual machines on that host computer. The host virtual adapter is used in host-only and NAT configurations.

The host virtual adapter is not connected to any external network unless you set up special software on the host computer — a proxy server, for example — to connect the host-only adapter to the physical network adapter.

The software that creates the host virtual adapter is installed when you install GSX Server (on a Linux host, you must choose to make host-only networking available to your virtual machines). A host virtual adapter is then created automatically when you boot the host computer.

You can set up additional host virtual adapters as needed.

The NAT (network address translation) device allows you to connect your virtual machines to an external network when you have only one IP network address on the physical network, and that address is used by the host computer. You can, for example, use NAT to connect your virtual machines to the Internet through a dial-up connection on the host computer or through the host computer's Ethernet adapter or wireless Ethernet adapter. NAT is also useful when you need to connect to a non-Ethernet network, such as Token Ring or ATM.

The NAT device is set up automatically when you install GSX Server. (On a Linux host, you must choose to make NAT available to your virtual machines.)

The DHCP (dynamic host configuration protocol) server provides IP network addresses to virtual machines in configurations that are not bridged to an external network — for example, host-only and NAT configurations.

One virtual network adapter is set up for your virtual machine when you create it with the New Virtual Machine Wizard using any type of networking (a virtual network adapter is always added to a virtual machine created with the VMware Management Interface). It appears to the guest operating system as an AMD PCNET PCI adapter.

You can create and configure up to four virtual network adapters in each virtual machine using the virtual machine settings editor.

The adapter can use one of two drivers. You can choose between the vlance driver, which installs automatically, and the vmxnet driver, which provides better network performance. The difference in network performance is most noticeable if the virtual machine is connected to a Gigabit Ethernet card on the host.