Windows Network Diagnostics Tool
Personally, I have never used the Windows Diagnostics Tool apart from the time when I decided to write a few lines about it. Most windows administrators would normally invoke other testing tools to troubleshoot network issues, however, for the less knowledgeable users the Windows Diagnostics Tool is an adequate solution that tries to automate the troubleshooting process. The tool button or link appears automatically when Internet Explorer cannot display a webpage.
Conversely, if you do not use Internet Explorer as your web browser you can access the tool from the Control Panel\Network and Internet\Network Connections window by right clicking the Local Area Connection interface and selecting Diagnose. The tool performs an automated troubleshooting task where it tries to fix the problem and suggests some solutions when it fails. The suggested solutions are based on the problems found and allow the user to re-test through additional steps.
You can also access the tool from the Network and Sharing center system tray icon which would indicate the problem with a red X mark. Right click on the icon and select Troubleshoot problems. The wizard allows you to perform additional diagnostics such as, allowing other computers to connect to your machine, establish DirectAccess connections and using specific network adapters. Windows Diagnostics Tool confirms that the problem is fixed by displaying a message indicating the problem and status as shown below: