What are Session state modes in ASP.NET?

ASP.NET supports different session state storage options:

• In-Process is the default approach. It stores session state locally on same web server memory where the application is running.
• StateServer mode stores session state in a process other than the one where application is running. Naturally, it has added advantages that session state is accessible from multiple web servers in a Web Farm and also session state will remain preserved even web application is restarted.
• SQLServer mode stores session state in SQL Server database. It has the same advantages as that of StateServer.
• Custom modes allows to define our custom storage provider.
• Off mode disables session storage.