<system.web>
    <authentication mode="Forms">
      <forms cookieless="AutoDetect" defaultUrl="index.html" loginUrl="Login.aspx" name=".AUTHPATH" protection="All" timeout="60" domain="sub.domain.ru" path="Cookie">
        <credentials passwordFormat="Clear">
          <user name="User" password="Password" />
        </credentials>
      </forms>
    </authentication>
        <authorization>
            <deny users="?" />
        </authorization>
  </system.web>

	<system.web>
		<httpRuntime requestPathInvalidCharacters="" />
		
    <authentication mode="Forms">
      <forms cookieless="AutoDetect" loginUrl="../Login.aspx" name=".AUTHPATH" protection="All" timeout="60" domain="sub.domain.ru" path="../Cookie">
    </authentication>
	
	</system.web>

<script runat = server>
 protected void btnLogin_Click(object sender, EventArgs e)
        {
            // Authenticate againts the list stored in web.config
            if (FormsAuthentication.Authenticate(username.Text, password.Text))
            {
                // Create the authentication cookie and redirect the user to welcome page
                FormsAuthentication.RedirectFromLoginPage(username.Text, false);
            }
            else
            {
                lblMessage.Text = "Неправильный логин или пароль";
            }
	}
</script>