The Microsoft Loopback adapter is a testing tool for a virtual network environment where network access is not available.
Microsoft Windows 2000 and XP (and probably others) ship with a built-in network interface driver called the “Microsoft Loopback Adapter” that lets you create a local-only network interface device. This adapter can be extremely useful when you are doing development testing using Virtual PC and want to isolate your Virtual PC’s from your main network.
Step # 1 – Install Microsoft Loopback Adapter
Manual installation in Windows XP
To manually install the Microsoft Loopback adapter in Windows XP, follow these steps:
1. Click Start, and then click Control Panel.
2. If you are in Classic view, click Switch to Category View under Control Panel in the left pane.
3. Double-click Printers and Other Hardware, and then click Next.
4. Under See Also in the left pane, click Add Hardware,and then click Next.
5. Click Yes, I have already connected the hardware, and then click Next.
6. At the bottom of the list, click Add a new hardware device, and then click Next.
7. Click Install the hardware that I manually select from a list, and then click Next.
8. Click Network adapters, and then click Next.
9. In the Manufacturer box, click Microsoft.
10. In the Network Adapter box, click Microsoft Loopback Adapter, and then click Next.
11. Click Finish.
If you are running Windows 7 host operating system, use the below URL for step-by-step guide: