We can use loopback interface with GNS3 for learning networking. This article will explain “how to add loopback interface” in Windows 7
1. Click Start Menu and type cmd.exe, then right click cmd.exe and click Run as administrator
2. from command prompt, type hdwwiz.exe and ENTER, another window will appear.
3. from Add Hardware Wizard, klik Next to continue
4. from below window, select “Install the hardware that I manually select from a list (Advanced)” and Next.
5. From the list, select “Network adapters” and Next.
6. Last step, from column “Manufacturer” select “Microsoft” and in the column “Network adapter:” select “Microsoft Loopback Adapter” and then click Next
7. Now in the Control Panel — Network and Internet — Network and Sharing Center — Change adapter settings, you can see new network adapter. You can add new static IP like another network adapter in your laptop/computer.