ASP and ASP.NET are server side technologies.
Both technologies enable computer code to be executed by an Internet server.
When a browser requests an ASP or ASP.NET file, the ASP engine reads the file, executes any code in the file, and returns the result to the browser.
ASP (aka Classic ASP) was introduced in 1998 as Microsoft's first server side scripting language.
Classic ASP pages have the file extension .asp and are normally written in VBScript.
ASP.NET was released in 2002 as a successor to Classic ASP.
ASP.NET pages have the extension .aspx and are normally written in C# (C sharp).
ASP.NET 4.6 is the latest official version of ASP.NET.
ASP.NET 5 was expected to be an important redesign of ASP.NET.
However, the development of ASP.NET 5 was stopped in favor of ASP.NET Core.