Session Expires within few 4 minutes - asp.net

Question

Recently i'm facing a problem of session timeout. User can logedin successfully but during his operation over few pages, Session times out within couple minutes(<4 mins).
Most recently when I moved my application on a new server be the inception of this. Before this my Web Application was working fine.
Please help me.
My webConfig settings are like shown
<configuration>
<configsections>
<sectiongroup name="system.web.extensions" type="System.Web.Configuration.SystemWebExtensionsSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
<sectiongroup name="scripting" type="System.Web.Configuration.ScriptingSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
<section name="scriptResourceHandler" type="System.Web.Configuration.ScriptingScriptResourceHandlerSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirepermission="false" allowdefinition="MachineToApplication" />
<sectiongroup name="webServices" type="System.Web.Configuration.ScriptingWebServicesSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
<section name="jsonSerialization" type="System.Web.Configuration.ScriptingJsonSerializationSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirepermission="false" allowdefinition="Everywhere" />
<section name="profileService" type="System.Web.Configuration.ScriptingProfileServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirepermission="false" allowdefinition="MachineToApplication" />
<section name="authenticationService" type="System.Web.Configuration.ScriptingAuthenticationServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirepermission="false" allowdefinition="MachineToApplication" />
<section name="roleService" type="System.Web.Configuration.ScriptingRoleServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirepermission="false" allowdefinition="MachineToApplication" />
</sectiongroup>
</sectiongroup>
</sectiongroup>
</configsections>
<appsettings>
<add key="CrystalImageCleaner-AutoStart" value="true" />
<add key="CrystalImageCleaner-Sleep" value="60000" />
<add key="CrystalImageCleaner-Age" value="120000" />
</appsettings>
<connectionstrings>
<add name="ConnectionString1" connectionstring="Data Source=xx.xx.xx.xx;Initial Catalog=xxxx;User ID=xxxx;Password=xxxx;" providername="System.Data.SqlClient" />
</connectionstrings>
<system.web>

Answer 1

Here is the code to set the time out for the session. If you are not using state serve r(mode:InProc) then the session will get cleared when the web.config is changed or the browse cache is cleared(for firefox) and also Review the config settings also.
<configuration>
<system.web>
<sessionState mode="InProc" stateConnectionString="tcpip=127.0.0.1:42424"
sqlConnectionString="data source=127.0.0.1;Trusted_Connection=yes"
cookieless="false" timeout="20" />
</system.web>
</configuration>