Original subtitles

You probably using it right now is

don't deny it.

You probably using DHEA P..

If you're watching this video whether it's on a device like this notice using DHEA P to connect to the

Internet or perhaps on a computer.

Modern networks rely very heavily on DHEA.

For example if you go to Starbucks or a coffee shop or you go to the airport it's very unlikely that

you're going to be walking around saying what's the I.P. address that I should be using.

Which IP address should I configure my device as very unlikely that you're going to be doing that.

And the reason for that is IP addresses are more often than not dynamically allocated especially to

client devices.

So here's an example of some client devices client devices could be pieces could be Internet of Things

devices such as these could be phones Servers typically have IP addresses configured statically because

you need to connect to that server.

So as an example if you go to Facebook dot com or some other Web site that domain name needs to be resolved

to an IP address and you need to connect to a specific IP address or range of IP addresses and they

are statically defined but more often than not client devices are automatically configured or dynamically

configured because it's too much work to manually configure these devices.

I mean when was the last time you manually configured your phone with an IP address.

Most of us probably have never done that or only in exceptional circumstances with Internet of Things

devices such as these lights or devices like cameras.

It doesn't make sense to manually configure IP addresses so as an example here's a IP camera.

I'm probably not going to configure this device statically.

I'm going to let it dynamically be configured now DHB or Dynamic Host Configuration Protocol is once

again a fundamental building block in networks today.

Okay but how does DCP actually work.

Do you know the messages sent between what's called a client and a server.

Do you know how they work in this video.

I'm gonna show you practically how to configure and use HP.

I've got a network here.

I'm going to demonstrate the HP using a router which I'll configure as a DHB server.

This is a Cisco wrote it but the same principles apply whether you configuring a home router or some

other kind of device as your DSP server.

I've got a Windows P.C. and I've got a Linux P.C. that are going to get IP addresses from the router

and I'm gonna run wire shock in this topology to show you how DHB actually works.

So rather than just talking about it I'm going to demonstrate it.

Here's an example of someone just talking about what the HP is rather than practically demonstrating

it.

Alexa what is DHEA P in computer networking the Dynamic Host Configuration Protocol D.H..

The network application protocol used by devices THC P clients to obtain configuration information for

operation in an Internet protocol network okay.

Not sure if you understood any of that but there you go.

There's a so-called definition of DHEA.

It's gonna make a lot more sense however if I show you this practically.

Now she did mention some terms there.

So let's look at some of those on this iPhone.

If I go to Settings go to my Wi-Fi network.

So in this example it's ABC 1 Top 5 gigahertz.

Go and look at the information I can see firstly that the address has been allocated automatically rather

than manually boot P is the predecessor to DCP.

It wouldn't worry about that.

Two main ways to configure IP addresses dynamically or automatically if you prefer that term or statically

where you manually configure the IP address on the device notice we have an IP address.

In this example it's 1 9 2 1 6 8 1 eleven.

We have a subnet mask 255 255 255 0.

We have a router 1 9 2 1 6 8 1 2 49 that is also known as the default gateway or the way to get to the

Internet.

So for a lot of people they don't understand necessarily the technical terms here.

They just want Wi-Fi and Wi-Fi equates to Internet.

So that's obviously not the same thing.

Wi-Fi is the way that we connect to a network using wireless technologies.

The Internet is a totally different concept and I won't discuss that right now.

But basically the broader or the default gateway is the way that you get typically to the Internet notice

we've got this option renew lease D.A. cheap IP addresses are typically only allocated for a period

of time when you configure the DHB server you as the administrator decide how long a lease is so you

can say the loss for three days or for a week.

You typically don't want to allocate IP addresses permanently even though you can in certain cases because

devices change as an example when you go to Starbucks you're not gonna be there permanently you're only

going there for a period of time a DHB pool or scope typically only consists of a range of IP addresses

so they may be only terms of 50 IP addresses in the pool or in the scope as people come and go.

We want to reuse those IP addresses so we only want to allocate them for a period of time at Starbucks

or other places they may reduce that interval to a much smaller period of time.

So that addresses are reused more often.

Notice this option configured DNS automatic or manual.

In this example the DNS server is the local router 1 9 2 1 6 8 1 249 that could be configured as 8 8

8 8 8 8 8.

That's a Google DNS server quite a famous one that once again is configured by the DHB administrator.

So that's an example of DHEA p on a client a phone.

We have many devices that use DHEA p i o t or Internet of Things devices such as these typically don't

get configured statically or manually it's too much work to configure it manually.

You're gonna want to do it dynamically.

This device as an example gives me a indication of the air quality in this room.

So my iPhone using IP is connecting to the information from that device so that I can see how good the

air quality is in the room.

I can talk to an Alexa Alexa start CCN a quiz.

Welcome to David bongos CCMA quiz.

I will ask you twenty four questions try to get as many right as you can.

Just say the number with the answer.

Let's begin.

Question 1 which of the following directions does T.P..

Okay let's play again soon.

So that device has been allocated an IP address by DCP that's connecting through Wi-Fi no physical ethernet

cables yet to the Internet.

So going to the default gateway.

Okay.

So without further ado I'm gonna show you practically how to configure DHEA P now and show you how it

actually works.

Okay so in this topology I've turned off the windows P.C. and the linux host I want to configure the

right of first and then once I've configured the right I want to run y shock on this link so that you

can see the DHEA message so you can see the entire thing happening I guess he hits the to show IPD HP

let's look at some options binding at the moment there are no bindings we haven't configured an address

pull yet an address pull in subscript terminology is very similar to a scope on say Windows or a another

platform I'm basically gonna create a pool of addresses and I'm gonna give it a name let's call it P.C..

This could be any name I'm gonna specify the network that is gonna be allocated and the subnet mask.

Now don't worry if you aren't used to Cisco commands similar kind of principles apply no matter what

device you're working on.

He I've got a home right.

This is a Beatty home router.

I'm based in the UK so British Telecom is my service provider.

This is the device that connects me to the Internet.

If I go to advance settings here on this device make this a bit bigger and go to home network and go

to it IP addresses.

What you'll see here is this is the IP address of the router so that would typically be my default gateway

if I connected to the wireless network or Wi-Fi network on this device.

There's the subnet mask the DHB server is enabled and I've manually configured a range of addresses

and I've specified the least time so last time in this case is three days.

Typically a host will try and renew its IP address halfway through the least time.

So that's an example on a home router in this example a British Telecom router on Cisco right as you

typically are going to use the CLIA or command line interface to configure the devices so the network

is once again this network that's similar in concept to specifying a range of addresses the way Cisco

could do it is you specify the network and then you specify what's called an exclusion range of addresses

that you want to exclude.

So typically you're going to want to exclude the routers IP address from the pool and perhaps other

network devices that you've got.

Okay.

So default gateway or default rather will be the local rider.

That's the IP address of the local rider.

I'll specify the DNS server as the local rider as well.

Now I know that IP address because I've configured this rider to use this IP address.

So I've basically configured show run shows me the configuration of the Cisco rider I've configured

the Cisco rider with a DHB pull.

This is the network.

This is the default rider or default gateway.

This is the DNS server very similar to this being the IP address of my B.T. rider.

This is the subnet mask that's being used and these are the addresses that are being allocated.

Now I haven't specified a least time I could do that.

So IPD HP pool P.C. many options are available here.

Many commands can be configured so I could specify lease and then specified number of days if I wanted

to or specify infinite.

Be careful with infinite because you could use up your pool of addresses.

So I'll just specify this time of one day I could specify a domain name as an example of let's say that.

So David bumbled dot com.

If I go back one step I could say IPD HP excluded addresses and let's exclude the router from the address

pool.

So on the right to show IPD HP pool I have configured a pool of addresses the pools name is P.C..

Total addresses in the pool is this.

This is the addresses in the address pool.

No addresses have been the least at the moment show run once again shows us that IP addresses in this

range will be allocated but this one won't default wrote a DNS of a domain name.

Okay so let's start y Ashok on the link between the switch and the router.

So why Sugar's running.

I can see various protocols here you can see as an example CTP spanning tree a bunch of protocols but

I'm gonna filter for the HP because I only want to see the HP messages.

Okay what I'll do is start the windows host first.

So this Windows piece is actually running as a virtual machine in my topology.

I'm running on a Mac here.

Genius 3 is a way for me to virtualize networks and I'm virtualizing a network of a Cisco rod a switch

a linux host and a Windows P.C..

So P.C. has booted up a logging I'm going to start a CRM deep prompt

and I'll make this bigger so that it's easier to read so IP config.

And I'm thinking Linux there should be IP conflict not I have config So IP config notice I can see domain

name I can see IP address that was allocated I can see subnet mask default gateway.

Now the reason this piece he used that address and not 10 1 1 1 is because that address was allocated

previously and it's just trying to get to the same IP address so IP address has been allocated I can

use the common IP config slash all to see more information.

So scrolling up again there's the command this is the hostname.

Now notice it's called M.S. age 110 that becomes important when we look at the why shock capture is

the domain name we can see the MAC address of the P.C. so this is the MAC address burnt into the network

interface call it I could see that as an example by going to control panel network and Internet view

network status look at my network interface card.

Notice if I click on details I'll be able to see the physical IP address and IP address information

in a similar way to using IP config.

I can also see when I go to properties that I'm using DHB obtain IP address automatically obtain DNS

server information automatically and using the IP conflict slash all command.

I can see IP address subnet mask.

Notice default gateway and DNS server information shown in the output here.