How to write a login system?
 

Can someone give me a few pointers on how you would set up a server which someone uses a username and password to access, and then it remembers who is logged on? Sort of like this message board, for instance, but my thing can't use cookies. My friend is trying to write an IM program by the way, that's what this is for.

he can use a database (mysql) to store the login information.... and connect to it through ODBC... this community is also writing an IM program... named Element, it can be viewed in the Projects forum...

You create a login page, post the information to a script which reads and verified the information with a database (most likely) manage on the back-end of the website, and if it passes than you forward to the member login page (after storing data into the session which identified that a user has logged in successfuly). If not logged in properly, send back to the login page with an error.

A few notes... 1) you may want to use HTTPS for a secure login page, depening on the level of security that you actually required, and 2) you will want to PASSWORD encrypt the password when you store and test for it in the database, it makes it more difficult for a hacker to get control of your database and see what the passwords are for each user (since they are encrypted).