I just curious to ask or know why people like to have IDS?I personally find it not very necessary cos your firewall will tell you all those hack attempts in it log files.Even though people may have already break through your firewall,what can you actually do with the IDS?It just only can alert you about the intrusion.What can you do to stop the intrusion is more important rather than alert you of the intrusion.If people hack into your system and what the use of of IDS which cannot stop it either. ^n^