You will often choose to network a virtual machine so that it can access network resources files and devices. The VMware application network features provide a good deal of flexibility for networking a VM.
You can define a VM to be entirely standalone, separate from any network and even from the host operating system. While a standalone VM cannot share any files or devices, it can be useful for testing and security purposes.
However, usually you will want to connect a VM to a network. The VMware application supports three connection types: bridged, host-only, and custom. The custom connection type, as its name implies, offers considerable flexibility in how you use networks.
Each VM running on a host machine can use a different connection type.
The VMware application uses virtual networks to support the various connection types. A virtual network is essentially a virtual Ethernet network that runs completely within the host machine. The VMware application automatically starts and uses as many virtual networks as are necessary (up to four, identified as vmnet0 through vmnet3). For more information about virtual networks, refer to "About Virtual Networks (vmnets)" .
The Network Connection Types
VMware supports three network connection types for a VM. (A fourth option is standalone, or no networking.) The bridged connection type is perhaps the most commonly used, as it offers the VM the most options.
A VM runs on a virtual network that is "bridged" to an existing physical network. The VM has a network address for the same physical network as the host operating system and appears on the network as a full-fledged host. This connection type provides the most network access to the VM; a bridged VM may transparently use any service on the network that it is bridged to, including printers, file servers, and gateways. Likewise, when a VM is bridged any physical host, or other VM configured as bridged, can use resources on that virtual machine.
a virtual machine can communicate with the host operating system and any other VMs on that host that are configured to use host-only networking. However, the VM cannot communicate with any systems off the host machine without the use of a proxy server. Host-only networking is most useful when the host itself is isolated or when you want to isolate your VMs from systems outside the host computer. This configuration is analogous to how corporations connect their internal networks to the Internet with a firewall and proxy services.
A VM can be defined to participate in a variety of complex network topologies. For example, a collection of virtual machines, possibly on multiple physical hosts might be configured on a private virtual network. This connection type can be used to set up a private file sharing environment, or to test a group of VMs in an isolated network environment.Although you can use this connection type if you have specific or unusual networking requirements, be aware that it requires more networking expertise and potentially the implementation of some simple user-level applications.
The remainder of this chapter describes the use of these network connection types.
Network Support Provided by the Host OS
The host machine provides VMware networking support using a virtual network device driver that implements four network interfaces identified as
Each interface is associated with a virtual Ethernet hub through which any number of virtual machines and the host can communicate. In addition to the network interfaces there are two applications:
Network support on the guest operating system appears through the virtual Ethernet adapter(s) that are configured for the virtual machine. Each device appears to the operating system as an AMD PCNET PCI adapter. Most operating systems recognize this virtual hardware and automatically configure use of the appropriate device driver. The main issue in completing network configuration in the guest operating system is assigning a network address for the virtual machine.
Using VMware Ethernet Adapters
Setting up networking for a VM entails hardly more work than setting up networking for a new PC. Briefly, you need to do the following:
If you choose any of the connection types (as opposed to Standalone), then you may need to perform some additional setup after you have installed the guest operating system. (For example, you might need to assign the VM a unique network address.)
The following sections assume the use of TCP/IP as the network protocol. If you use a different network protocol, then you may need to tailor the setup tasks in the guest operating system as required for that network protocol.