ASP.NET supports Three types of session modes that are

1.InProc – In Process
2.StateServer
3.SQLServer
This mode is set in the Configuaration File

In InProc Mode….. Session Objects and Variables are keep in a Slot of Cache

When using StateServer u have to specify the IP address of remote machine
When SQLServer u have specify the ConnectionString.

that config file tag is

 <sessionState
   mode="Off|Inproc|StateServer|SqlServer"
   cookieless="true|false"
   timeout="number of minutes"
   connectionString="server name:port number"
   sqlConnectionString="sql connection string" />blockquote>