My web.config
<sessionState mode="InProc" />
My Global.asax
void Session_Start(object sender, EventArgs e) 

        Session.Timeout = 1;
        string CookieHeaders = HttpContext.Current.Request.Headers["Cookie"];

        if ((null != CookieHeaders) && (CookieHeaders.IndexOf("ASP.NET_SessionId") >= 0))
            // It is existing visitor, but ASP.NET session is expired
Then I have 3 pages: default.aspx, page1.aspx and page2.aspx

When I access default.aspx and leave it idle for more than 1 minute I get redirected to expired.aspx as I was supposed to.
But if I click page1.aspx I will not be redirected to expired.aspx again anymore.
Id like to get redirected no matter what page Im surfing on and Id like to control that in just one place if possible, avoiding to have "if(something) redired to xxx.aspx" in every single page.

What should I do to make that happens once my session has expired?