Welcome to WebmasterWorld Guest from 18.104.22.168
Want I need to happen,is to make all pages after the login page unattainable, so if a user needs to view a page he would have to login again.
Per se bookmarking is totally under control of the end user - you can have some funny games with POST requests which are hard (if possible) to bookmark, but this is not good way of solving your problem.
If you want to allow access to only authenticated users then your pages after login page should check for login cookie(s) set by the login page, if cookie(s) not set then ask to login then show content relevant to the page originally requested.
1. login page - check username/password against database of allowed users, and if all matched then set cookie that will indicate that this user is authorised.
2. content page - if cookie is not set, then redirect to login, otherwise show content.