Help to defend from DOS web attacks

["Emanuel Marufo" <marufos () gmail com>]

Hello,

Recently somebody attack my web server, and i thinking defend from that.

I readed the next article:
http://www.quadrunner.com/index.php?option=com_content&task=view&id=151&Itemid=2

but i want to know if can config a snort/portsentry to block attackers ip's.