How to prevent a DoS attack!?

Not even sure what it is exactly..but i am making a website in php and am getting a large # of users. what is it and how to prevent it/

A DoS attack is a so-called Denial Of Service attack and has nothing to do with your PHP code. Try google for more info.

how come forums such as phpbb have mods that can prevent DoS attacks?

Because phpBB does everything arse-first.

A DoS attack is designed to over load your server. Think of it as someone/many people requesting a processer intensive page thousands of times per second so that valid users can't connect.

If you're using a webapp module to "prevent" DoS attacks, then you're still letting them hit your server, sure you may be doing a few less processor intensive things and this may save your arse, but you're just holding off the inevitable.

The best way to deal with this is to not let DoS style attacks near your webserver in the first place - use something like apache's mod_security or mod_dosevasive/mod_evasive to automatically drop abusive IP addresses at your firewall - before they get anywhere near your webserver.

--Simon

Moved to Security Forum.

A good way to prevent a DOS attack and future DOS attackes would be to install the apache module mod_dosevasive. This apache module will help protect against people sending too many requests to the webserver in an attempt to flood it. If it detects too many connections the offending ip will be blocked from the accessing apache for This is especially useful when the server is continuously getting attacked.

If you need the download let me know.

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www.firmbit.com