In this video, we're going to look at IP version for addressing.
I'm going to give you an overview of IP version for addresses and explain the basics of IP version for
addressing.
From now on, I'm going to refer to IP addresses, but be aware, please, that I'm discussing IP version
for addresses in this video and not IP version six addresses.
We're going to look at an overview of IP addresses, what they look like and how they function.
I'm going to explain the various address classes that you get, an IP version four.
In other words, class A, class B, class C, clause D and class E.
We'll also talk about CIDR or CIDR and how that changes the address classes.
But as a foundation, it's important that you understand the five address classes, ABC, D and E.
We'll look at special IP addresses, including the loopback address, the local broadcast address and
other special addresses.
And lastly, I'm going to explain what network mosques do and why they are important with regards to
IP addressing.
So what is an IP address?
An IP address is a layer three logical address assigned by an administrator.
Unlike MAC addresses, which are hard coded or burnt into network interface cards by the manufacturer,
an IP address is configured by an administrator.
The IP address may change within a subnet.
For example, when using DHCP or dynamic host configuration protocol, an IP address resides at a layer
three in the OCI model.
Please refer to the OCI videos for more details on how the OCI model works.
An IP address is used to uniquely identify a device on the network and is used by routers to determine
where that device is.
So a router routes traffic to a destination IP address based on a hierarchy of network and host, which
we'll talk about in a moment.
So once again, the IP address uniquely identifies a device in a network in a similar way to how houses
are uniquely identified in a street.
Houses in the street have a unique address.
So, for example, ten Oxford Street, in the same way, a host in a network has a unique identifier
on that network being its IP address.
I'm going to expand on that analogy in the next few minutes.
Every device on the Internet has a unique IP address, so there are millions of IP addresses out there
and no two devices can have the same IP address for communication on the Internet.
Every device needs a unique IP address and hence the move to IP version six these days because of IP
version for address exhaustion.
So for example, you cannot have a device 10.1, 1.1 communicating with another device with the same
IP address that's going to cause a conflict in the network.
Every device on the Internet has its own unique IP address and requires a unique IP address for communication.
Now I will be talking about RFC 1918 addresses in a moment in that RFC private IP addresses are explained.
So ten .1.1.1 is an example of a private IP address as specified in RFC 1918.
In a lot of organizations today, private IP addresses are used internally and then those addresses
are netted or network address translated onto the internet.
So when a device with IP address ten 111 is noted to a public IP address such as 12 at one point, 1.1,
the public IP address in this case, 12 .1.1.1 needs to be unique on the internet for now.
Just understand that IP addresses on the internet need to be unique from each other.
Network address, translation or NAT once again is not covered in this video, but I will be discussing
that in the set of CNA videos.
So be aware that in the real world multiple companies may use IP address 10.1 1.1.
But those addresses are netted to unique IP addresses when those devices send traffic onto the Internet.
Now here's a quick demonstration of some IP addresses.
If I ping w WW dot yahoo.com, notice that the domain name is translated to an IP address.
So in this case, yahoo.com is translated by a protocol called DNS or domain name service to an IP address
of 87.248 112.1 81.
DNS is used to convert easy to read names to IP addresses.
It's much easier to remember a simple name such as Yahoo.com or Cisco or BBC.co.uk, rather than having
to remember the IP address of those domain names.
As an analogy, this is similar to a phonebook where we are translating human friendly computer names
to IP addresses.
But what I'd like you to notice is that the IP address of Yahoo.com was resolved and we got an IP address
of 80 7248112 181.
I could ping another website such as abc.com.
Notice the IP address is translated to 15 one 9245 139.
Now a lot of websites don't permit pings, which uses ICMP, so the request times out.
But notice that the DNS server did resolve App.com to a 15 address.
Now in a moment, I'm going to explain what Class A addresses are.
But for this example, HP own the 15 class a public address range.
So anything that starts with 15 in the first octet belongs to HP.
Here's another example.
I'll ping google.com.
Notice in this case it resolves to 74 125 to 3350.