Take advantage of the open source library Serilog to log your ASP.NET Core application’s data to SQL Server or another database target.

Use custom-built .NET Framework 4.0 classes to connect an ASP.NET Web application to a SQL Server 2012 database.

ASP.NET sees the session cookie and loads the session (or doesn't, and starts a new one). This is why people recommend serving static, unauthenticated resources like images from a separate domain.