GetBaseException and InnerException

[mendhak]

In my Global.asax file, I'm working with the exceptions like this:

Dim context As System.Web.HttpContext = HttpContext.Current
        Dim ex As System.Exception = context.Server.GetLastError.GetBaseException()

Now the question is very simple:

What is the difference between GetBaseException() and InnerException, and which one should I be working with?