ASP.NET forms authentication

To implement a form authentication, you need add the following code in web.config:

<system.web>
  <authentication mode="Forms">
    <forms loginUrl="logon.aspx" timeout="60" enableCrossAppRedirects="true" name=".ASPXFORMSAUTH">
    </forms>
  </authentication>
  <authorization>
    <deny users="?" />
  </authorization>
</system.web>

enableCrossAppRedirects means authenticated users in this application can be redirected to other applications as authenticated too.

<deny users="?" /> means that unauthenticated users (represented by "?") are denied access to resources in this application.

In default page:

protected void Page_Load(object sender, EventArgs e)
{
HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.NoCache);        
CookiesManager.RemoveAll();
FormsAuthentication.SignOut();			
Response.Redirect("Logon.aspx");
}

HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.NoCache);set no browser cache.

FormsAuthentication.SignOut(); will remove authentication information from cookie for current user.

CookiesManager.RemoveAll(); will remove browser cookies for this application

In Login.aspx:

<div id="Fieldsetcontent">
<asp:Login ID="LoginPage" runat="server" DisplayRememberMe="False" TitleText="" OnLoggingIn="Page_LogIn" />
</div>

In Login.aspx.cs

protected void Page_LogIn(object sender, LoginCancelEventArgs e)
{
//Authentication code
}