The custom network connection type offers the most flexibility, but requires the most expertise and setup. For example, you can explicitly define each network that a VM will belong to. This allows you the most flexibility, as demonstrated in some examples below.

Following are some situations when the custom connection type might be useful.

• You want to network a set of virtual machines on different host machines, but you do not want to include the host machines on the network (that is, you would like a virtual intranet).
• You would like to set up a particular network for teaching or testing purposes.
• You need a network on which to test network utilities.
• You would like to leverage the IP address space available to you.

To use custom networking, you use the standard OS utilities to create a virtual network that includes one or more VMs (and physical machines if desired). These virtual networks are identified as vmnet2, vmnet3, and so on. The number assigned to the network is set when the first machine on the network starts; this number can change, but you never use it directly.

Depending upon how IP addresses are assigned to the virtual machine(s) the host operating system acts either as a gateway/router for the network (if the VMs use visible IP addresses) or as a masquerade to external networks.

There is no one way to define a custom network. For some ideas and examples of using the Custom connection type, refer to the VMware Web site technical support pages.