You Can Create session, and take ths value on every page and define the roleId, If a user have authentication then he can open tha page, other wise he cannot ope the page, ther is some code with the help of this code you can solve your problem.
string strCurrentRole;
try
{
strCurrentRole = Request.QueryString["RoleId"].ToString();
if (Session["Admin"] == null || strCurrentRole != "04" || Session["Roles"].ToString().IndexOf("04") == -1)
{
Session.RemoveAll();
Response.Redirect("Default.aspx");
}
}
catch
{
Session.RemoveAll();
Response.Redirect("Default.aspx");
}
There is role id whic you can define on your page.