PowerShell: use PowerShell behind the proxy server

1、 Technical specification ：

1） If your computer is on the company network behind the proxy server , By default, you will not be able to start from PowerShell CLI External access Web resources .

   -  You can't use commands  Invoke-WebRequest Get the outside  Web  The content of the web page .

   -  You can't use commands  Update-Help  Get help updates .

   -  Cannot use command to connect to  Azure/Microsoft 365.

   -  Cannot from  PSGallery  install  PowerShell Module  or  RSAT Capability.

   -  Not from the outside  Package Repository  download  Application Package.

2） When using  Update-Help  When updating help , The following error message appears ：

   Update-help : ...... Unable to connect to Help content. The server on which Help content is stored might not be available. Verify that the server is available, or wait until the server is back online, and then try the command again.   

3） When using  Invoke-WebRequest  Get the outside  Web  When the page is , The following error message appears ：

   Unab