This article was written about products for which Microsoft no longer offers support. Therefore, this article is offered "as is" and will no longer be updated.
This article describes how to connect multiple virtual machines together on the same host computer without an external network connection.
To connect multiple virtual machines together on the same host computer without an external network connection, configure the Networking setting on the guest operating system to use Virtual Switch networking with the Local only option.
With Virtual Switch networking, you can configure an isolated virtual network where servers and clients can run without affecting a production environment. To use the Virtual Switch, you must have an active network card or the Microsoft Loopback Adapter. You may install the Microsoft Loopback Adapter on a computer that is running Microsoft Windows NT 4.0, Windows 2000, or Windows XP when there is no active network card.
Note Because there are several versions of Microsoft Windows, the following steps may be different on your computer. If they are, see your product documentation to complete these steps.
To install the Microsoft Loopback Adapter, follow these steps:
Click Start, point to Control Panel, and then click Add Hardware.
Click Yes, I have already connected the hardware.
In the Installed hardware list, click Add a new hardware device, and then click Next.
Click Install the hardware that I manually select from a list (Advanced), and then click Next.
In the Common hardware types list, click Network adapters, and then click Next.
In the Manufacturer box, click Microsoft, in the Network Adapter list, click Microsoft Loopback Adapter, and then click Next.
To configure the guest operating system to use Virtual Switch networking and Microsoft Loopback Adapter, follow these steps:
Start Virtual PC (if it is not already started).
On the File menu, click Preferences.
In Global Setting list, click Virtual Switch.
In the Network adapter list , click Microsoft Loopback Adapter, and then click OK.
To configure the networking settings on the guest operating system to Virtual Switch, and then to set the Virtual Switch to Local Only, follow these steps:
Click the guest operating system that you want to configure, and then click Settings.
In the PC Setting list, click Networking.
In the Networking list, click Virtual Switch, click Local only, and then click OK.
Note In all host operating systems except Windows XP, you can have an active network link for Virtual Switch to function. For Windows XP, you can create a network bridge for local networking. Windows XP is only supported in Virtual PC 4.2 and later.