Original subtitles

Now we've been told to configure of one with the lost IP address in the that subnet.

Now this is the subnet that we concentrating on initially so let's start with that subnet.

The way you work out first.

Lost and broadcast addresses as follows.

The network has the host portion populated with binary zeros.

So notice whose portion is all zeros.

The first host has the host portion populated with binary zeros except for the lost but which is set

to a one in binary.

So that's the first host in the subnet The Lost host in the subnet as the host portion populated with

binary ones except for the lost but which is set to binary 0 and I'll show you in a moment what that

is but it's easier to work out the broadcast address first.

So the broadcast address equals that subnet

and the host portion is populated with binary ones.

So it's 1 1 followed by 4 ones.

Now you can work this out by saying 32 plus 16 plus eight plus four plus two plus one.

But I find it easier to do the following if this is set to 1 and everything else is set to zeros so

it looks like this that equals 64 one less than that equals 63.

So if you asked for something like this what is the broadcast address.

Have a look at the next subnet and subtract one to get to the broadcast address of the previous subnet.

The next subnet is 1 9 2 1 6 8 1 64.

The broadcast address of the previous subnet is that subnet minus 1.

So in other words it's 63 and then this is 62.

So for this subnet that's the network and first host This is the lost and broadcast address.

Second lost which we need for this switch is essentially one less than that can work out the binary

but it may be easier just to subtract one from the decimal.

So that's 61.

And the third lost is one less than that which is 60

so we now know the network the first host the broadcast the lost host.

Second lost host and third lost host.

Easiest way to work this out is to work out to the network and then work out the next network one less

than the next network gives you the broadcast address for the current subnet and then you can just subtract

one from that to get to the lost host.

Second lost host and third lost host first host is equal to the network portion plus 1.

So they are our values.

That means we can now configure this router with the lost IP address in the subnet.

So currently on this router it only has a loop back interface configured it it doesn't have an IP address

configured on gigabit.

0 0 0.

Remember the network 1 9 2 1 6 8 1.0 slash 26 has two bits that are part of the network portion two

binary bits.

Looks like that which equals 192.

So we can configure the gigabit.

0 0 0 interface with an IP address of 1 8 2 1 6 8 1 62 because that's the last IP address in the subnet.

So 62 and the mask is 2 4 5 2 4 5 2 4 5 1 92.

And that's because these two bits are part of the network.

So we've got 255 255 255 two bits there which equates to 192.

So show IP interface brief we can now paying our local IP address.

The switch needs to be configured with the second a lost IP address in the subnet.

Per these instructions so configure the switches with the second lost IP address and then the DHB servers

with the third lost IP address.

So again he has I'll switch

I'll give it a name.

Switch one interface of Ilan one no shut IP address 1 9 2 1 6 8 1 and the next IP address that we can

use is 60 1 2 4 5 2 4 5 2 4 5 1 92.

So show IP interface brief that's the IP address of the switch can the switch now ping the router yes

it can switch has been successfully configured router has been successfully configured let's configure

the DHB server so on the Ethernet interface we going to configure a static IP address of 1 9 2 1 6 8

1 and the IP address will be 60 in this example third lost IP address subnet Moscow will be 2 4 5 2

4 5 2 4 5 1 92.

Now the default gateway will be the router 1 9 2 1 6 8 1 and the Rada once again has IP address 62 so

62 DNS server and this example will be 8 today to today to date this is the internet DNS server it's

configured with DNS names for Cisco dot com and Facebook dot com so the server has been configured.

Can we ping the switch.

Yes we can.

What about the router.

Yes we can.

So we've configured IP addresses and default gateways on the network devices.

Now one thing I still need to do on the switch is specify a default gateway which will be the router

Rod it has IP address 62

so again the switch can ping the router we've finished configuring the switch now on the DHB server

we need to configure a DHB pool default gateway is going to be the router 62 DNS server is going to

be the Google DNS server and we can allocate IP addresses from 1 9 2 1 6 8 1 2 1.

So from the first ip address in the subnet to a number that we decide.

So we could as an example allocate 100 IP addresses so I'll save that.

So we've specified the pull name default gateway DNS server starting IP address in the pool and the

number of IP addresses that can be allocated now can I specify a hundred hosted addresses the answer

is no I should actually specify only something like 50 because of the subnet only supports 62 IP addresses

so remember the formula 2 to the power of something which is the number of but minus 2 gives you the

number of hosts that are supported in a subnet.

Yeah we've got six binary bits.

So two to the power of six.

That's the number of bits in the WHO's portion what's two to the power of six two to the power four

is sixteen two to the power of five equals thirty two.

Two to the power of six equals 64 so 64 minus two gives us sixty two hosts that are supported in a subnet

but we want to allocate some of those IP addresses to network devices so we don't want to allocate the

full submit to the DHB server we'll only allocate a portion of the addresses to hosts via DCP so on

P.S. One does the piece you have an IP address yes it does it's been allocated 1 on 2 1 6 8 1 dot 3

cannot ping the default gateway yes it can.

P.S. 1 as an example IP config it's also been allocated an IP address 1 9 2 1 6 8 1 2 2 cannot ping

its default gateway yes it can and on P.C. to do something similar.

IP address has been allocated and it can ping its a default gateway so we've successfully configured

subnet 1.

Now we need to configure the serial link and then once I've done that I'll check whether these devices

can access devices on the Internet and then I'll configure the other subnets.