So we mentioned that we have different I p v for dressed classes. Now those are actually the way that we categorise different i p address ranges and give them different number of network ideas and host cities. We also have
difference between what we call public I p addresses in private I p addresses. Now, when we're talking about public I p addresses these, we're going to be addresses that are globally row double on the Internet
are there actually globally unique
across the Internet. Let's say we have a computer in our home that's acting as a Web server and we have a website. We have a Web page on that server, and we want
people to be able to access that Web page well.
Our Web page will be given a public I P address that either is given to us through or usually even to us. There are Internet service provider will get a public I P address and then use that public I P address to associate with that Web page
so that when anybody tries to go to our Web page, it'll connect them to that public I p address and get them to our server. So we're just sitting out here and we have our server and our website, um
www dot cyberia dot i t And then
that cyber dot i T website is given its own public i p address.
So let's say that this public I p address we'll just go with this is a random set of numbers, by the way. 1 91 dot to 21.7 dot two. We have our i. P address for our Web server here Now, anyone from anywhere in the world
with a connection to the Internet
so long as we're connected to the Internet,
Congar out to the Internet and get to our Web server.
Now this is great. People can see our website. People can view our videos. People can learn about i t.
we have our computer here
and we have an I P address too, because we need to contact them.
Well, we don't really want just anybody in the world
connecting to our computer. We don't want someone over here being able to just go through and connect us directly.
So that sort of prevents a problem. How do we make sure that we can talk to people
outside on the outside and talk to different websites
but prevent someone else from just connecting directly to us, connecting directly to our computer well again. That's where our public versus Private I P addresses come in handy
again. Our public I P addresses are going to be
globally rideable globally unique.
No one else in the world except this. This one host is goingto have
that I p address is only going to go to one single host.
And again, these must be purchased and assigned through your Internet service provider,
and they need to be set statically, especially for
Web server instances. We want them to be set statically because we don't want this to be constantly changing because that would prevent people from accessing our website. Now a typical home user does have a public i p address, but our Internet service provider will change it quite often. Now that public I p address isn't on your individual computer. It's
really used by your out
facing router, so we're back to our situation. We're trying to connect to this computer to our Web server here, and we have our computer over here and we're trying to connect out
us just going cooked directly through the Internet and are one computer device connecting directly over the Internet to that server our Internet service provider gives our router, which we have here
its own public I p address again. Normally these unless you've specifically been assigned a static public I p address for your router. This may change,
so we'll say that our
routers public facing I p address is 10.17 dot 8.1. That's our routers public facing I. P address. Pretty much what routers do is
in their name. They route the route information. They route it from being one type of address, 11 network to another network. So it has a router has to i p addresses. It has this public address, and then it also has something called our private address. What is our private address?
Well, our private address isn't it
non row doble address. That address doesn't get routed over the internet.
Now, when I say non row double, I don't mean that
well, since will have an address and we'll go to our I p address and we'll go to our I p router and we can't go anywhere. Non row double just means that someone else on the Internet Internet can't try to connect to that address and just get there directly. That address isn't globally unique,
and these addresses thes private addresses are on lee, reserved for internal use inside of one router. So we have
your computer in your home. But you also have
that connects to the Internet and you have your laptop, which also connects to the Internet. And all of these devices get private I p addresses. So our router here it has its public address that is out facing that's looking at the Internet. And then it has its private address. 1 92 That 1 68
That's our routers. Private dress. Now, if that's the same private address that you use in your home, they'll be suddenly shocked that I figured out what it was. That's a very common private address that people use for routers. That 1 92.1 68.1 network is very common, so you go into
a different location, use their wireless or
go to someone else's home and connect to their wireless.
You may see that in quite a few different places.
So with these computers here,
they've now been all assigned a private I. P address. This one is 1 92.1 68 not 1.2.
1 92.1 68.1 dot three. Then our phone is
1 92.1 68.1 dot for this computer here that we're on right now says, Hey, I want to talk to cyber it out. I t
because my address is non row doble.
But the routers address is rideable.
take our i p address, make a note of it,
take our requests for information
and using its public i p address, pass it over the Internet
to our cyber dot i t Web server
that I cyber readout I t Web server will process that request,
get the information we want
and send it back over the Internet
with the intent of getting to this public i p address, which is our router, not our individual computer, but our router,
and now it gets there.
So it sent that information over the Internet
to our router, and the router remembers. Oh, this is the information that was requested by
this private i p address.
So now it takes that information that it received that request that we received
incident passes it on to us. So we see about how use we see how, by using public and private i p addresses
we reserved and we reserve private I P addresses to our internal network
and public I p addresses to Internet wide, globally wide networks. We can
have it set up so that
our internal networks they a little bit more secure than having every single device with individual public I p addresses. And we also see how we haven't run out of I p before addresses. Yet if every single individual
Internet connecting computer on the planet had a public facing I p address, we would've been out of I p addresses a long time ago.
All the billions of computers that are on on planet Earth all the billions of phones and tablets and
refrigerators that connect to the Internet now that are on planet Earth, we would have run out of public I p addresses a long time ago. But thanks to our private I P addresses which are on Lee contained within are one network versus our public I p addresses.
We're able to retain that. Still, we still have
the ability to use R I. P D four addresses and we haven't completely used a mullet. Used them all up yet. What are our private I p address ranges? Let's go ahead and got those down real quick. We're talking about our i p address ranges. We're talking about the ranges of 10.0 dot zero slash eight.
So we have our network i d. In our host i d.
And then we also have our 1 72.16 dot 0.0 slash 12.
cider notation of Dash 12
isn't quite critical as to how it lines up with our bits to know for the A plus exam. But just you just want to know that that 1 27.16
is where is a private address private address range. So if you see that that's private
and then we have 1 92.1 68 0.0 flash 16 We see here How again? R Tenn 160.0 dot zero
1 72.16 dot 0.0 and are 1 92.1 68 0.0
Are all three going to be our private I P addresses address ranges, and they're all going to be networks that use
private I P addresses and aren't rideable over the Internet. So you'll see them very common for internal addresses. And they're the types of addresses that you want to set for internal use computers, especially because that's the only way they're going to be successfully able to communicate over the network. And the only way that we can get them talking on are not only our network
but to connect to other computers
through our router and over through the Internet.