I've got a little network right here.
So this yellow box is going to be my switch and these individual little cylinders are going to be my
host and this guy right here is my connection to the Internet.
So he's just going to be at this moment.
Well just a router.
Now when we look at this network it's really really important to us that well we don't let naughty things
happen to our network.
So within the Internet world the first line of defense is going to be a firewall.
And now the firewalls main job is to prevent naughty things from the outside world coming into our network.
So traditionally a firewall is going to be right here.
So that's why so many routers also have built in firewall features.
Now our router doesn't have to have that if we wanted to we can go out and buy a specialized firewall
device.
And now we can have our router and then our firewall as its own separate device Barracuda pedicle a
lot of people will sell you a box like this and this thing's been updated so it's always aware of evil
things that are out there.
And so this is not an uncommon setup.
So we've got some kind of router we've got some kind of firewall.
And then we have our network itself now.
Firewalls are great and we certainly discuss firewalls in other episodes but we have another problem
here and that is that firewalls are imperfect.
So if I have an imperfect firewall I need to have something inside the network that's watching for naughtiness
to happen.
And that's where intrusion detection systems come into play and intrusion detection system can just
be a computer with specialized ideas software or it could be a specialized device but by nature intrusion
detection tends to be on the inside of a network.
So here I'll just plug them into my switch and his job is to watch for naughty things on the network
itself.
If he detects something on the network it's the idea his job to let somebody know in the early generations
of ideas.
This would be done with those they would send an e-mail to somebody or hit their page or yeah they are
that old today.
You'll get a text message or something like that.
So again it doesn't matter to me.
This can be a specialized device or it could be a Windows machine running specialized idea software.
Now this is the first generation of intrusion detection.
Now over time we began to get intrusion detection that became what we called active.
So this box would say Oh I notice that there's a well-known attack coming in here.
And what he could do would be to talk to the firewall itself and say hey firewall shut off a porter
stop particular application or do something to stop this attack.
And we called that and I am using the past tense active IDs active ideas is really what we call intrusion
prevention now or IPX an IPA system does the same thing as an idea.
It's looking on the inside of the network for naughtiness.
But it does something to stop it.
Now if I have a device way over here it has a hard time stopping things because it's not actually in
line.
So what we usually see with IPX
is something like this.
This is getting long now again we can have routers that have IPX built in them we can have firewalls
with IPX built into them but you can actually still buy IPX boxes whose only job is to provide IPX features.
Now assuming we have something like this this box right here is tends to be in line and it is certainly
monitoring the internal network.
But if it catches something in here it's going to do something here to stop it.
And that's the big thing you need to be aware of when it comes to ideas versus IPs on the network plus.
Oh and by the way make sure that you can handle any question that defines the difference between a firewall
versus an ideas versus an IP as
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on
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