need help with user authentication routine

[walterbyrd]

I am trying to develop a simple user authentication routine.

I started with something I got from a book called "PHP in Easy Steps."
It works like this:

- create a table in a database with basic user information: name,
login, password
- create a simple html form which loads "authenticate.p hp" when the
submit button is pushed.
- autheticate.php checks the login against the database, and loads the
next file, if the user is authenticated.

I have all that working. The problem, if you haven't guessed, is that
somebody can bypass the entire thing, if that person the the file(s)
that are loaded after the authetication. i.e.

http://urlname/sensitivedata.html

So how do I fix this? Cookies? Can I check if the user is authenticated
in each subsequent file that might be loaded?

[crucialmoment]

Re: need help with user authentication routine

There are a lot of different methods that can be used.
Start here

http://us2.php.net/manual/en/ref.session.php

I find it helpful, especially in areas such as session management, to
view the code of others who have spent time getting it right. Just
about every open source bb app or content management app includes an
authentication piece you can learn from.

phpclasses.org is a valuable resource for learning from other's code.
(Although object based php might be a little confusing for someone just
getting started)
This link will search phpclasses for authentication

http://www.google.com/custom?domains=www.phpclasses.org&q=authentication&btnG=Search&sitesearch=www.phpclasses.org