What is IDS?
IDS is an acronym for Intrusion Detection System. An intrusion detection system detects intruders; that is, unexpected, unwanted or unauthorized people or programs on my computer network.
Why do I need IDS? A network firewall will keep the bad guys off my network, right? And my anti-virus will recognize and get rid of any virus I might catch, right? And my password-protected access control will stop the office cleaner trawling through my network after I've gone home, right? So that's it - I'm fully protected, right?
A firewall has got holes to let things through: without it, you wouldn't be able to access the Internet or send or receive emails. Anti-virus systems are only good at detecting viruses they already know about. And passwords can be hacked, stolen or left lying about on post-its.