This is one of multiple IP addressing and submitting scenarios rather than just working out the subnets
for a scenario.
We're going to work them out and then configure the devices so that we can practically design and configure
a Cisco IP network.
So we've successfully configured this subnet.
Now we need to configure this subnet and this gets a little bit more interesting because it's 1 9 2
1 6 8 1 64 slice 26.
So we already know what the subnet address is.
Now we need to work out what the first host addresses.
So what is the first host for the network
now to work out to the first host.
You make the host portion zeros except for the last but which is set to 1.
But to work out the decimal value over here you need to look at the entire octet.
So this is 64 because that's the network plus one is 65.
So the first host is 65.
What does the last host.
The easiest way to work that out actually is to do broadcast first and then work out the last host.
So for the broadcast what we do is we fool the host portion with binary ones.
So what is that.
It's 255 less 128 which is 127.
So the broadcast address is 1 9 2 1 6 8 1 127.
Now the last host is one less than the broadcast address.
So for the last host we set the host portion two binary ones except for the last but.
So what does that equal to that's equal to 126.
So let's assume that we configure the right over the last IP address in the subnet and then we going
to enable DHP on the router to allocate IP addresses to the hosts.
So you just wrote it to on the fast ethernet interface I'm going to shut the interface and then I'm
going to configure an IP address as we worked out 1 9 2 1 6 8 1 1:26.
And then we need to specify the subnet mask 2 4 5 2 4 5 2 4 5 1 2 second we paying
our local address.
Yes we can.
Now for host allocation let's use DHP.
So it create ADHD the pool with a name New York and here we need to specify the network.
So what is the network it's 1 2 1 6 8 1 64.
And here we have an option we can either use slushed 26 or the dotted decimal notation.
So let's use Sajda or flush 26 do show run will allow us to see our configuration.
So that's what we've done in the DHP pool.
Now we need to configure a default gateway.
So our default gateway is going to be 1 2 1 6 8 1 1:26.
There are other options that we can specify in DHP such as DNS server.
And in this case let's set the DNS server to the local rodder in the real world you probably have a
separate DNS server.
So show run
this the DHS people that we've configured we've configured the default gateway or default router and
DNS server now in the hosts.
Let's see if they get IP addresses
so on the hosts we are going to configure them to use DHP rather than static IP addresses.
So let's do that on both hosts are both PCs.
Change them to use DHP.
And then let's start them up and let's see if they get an IP address from the DHP server.
Open up a console to both of them.
So here you can see the first host got an IP address 1 9 2 1 6 8 1 65.
And the second host got an IP address of 1 2 1 6 8 1 66.
So can the second host ping the first host.
Yes it can.
Will it be able to paying the default gateway.
Let's try that.
Yes it can.
So we've successfully configured the New York site with an IP address on the default gateway and we've
set up a DHP.
Now one thing you want to do when you set up a DHB pool like this is specify the excluded address.
We don't want the DHP server to allocate its own address so we can use the common IP DHP server
or rather IP DHP excluded address.
And we can specify a range of addresses to exclude and this example will only exclude local routers
IP address so we excluded the local routers IP address which means that it won't be allocated through
DHP.
I'll save the routers configuration and while we help save Rotto one's configuration
OK so at this point we've configured both San Francisco and New York.
The next step is to configure the when connection.
Now it's inefficient to use a subnet that supports 62 hosts for a network that only requires two.
But for now lets start off by using the subnet that we allocated.
And then in a subsequent video I'll show you how to optimize this one.
Let's allocate to the first IP address in the subnet to the Rodda.
So that's essentially one more than the subnet address.
So one twenty nine and one more than that.
Would be 130
with subnet mask so what you'll notice is the first IP address is one more than the subnet address and
the last IP address is one less than the broadcast address so we need to know shut these two interfaces
and what should happen now is rodder one should be able to ping router to which it can.
So we've successfully configured the IP addresses on the when and on both landing to faces but to enable
full connectivity in this network we need to run a writing protocol.
And in this example all run Joe GOP and enable the GOP on network 1 2 1 6 8 1 2 0.
Now that is a class full network.
In other words it's looking at class-C 1 9 2 1 6 8 1 2 0 and not to the subnet addresses on the side
we'll do something similar.
Network 1 2 1 6 8 1 2 0 0.
Disable automatic summarization so that they don't automatically summarize any network's show IP our
job he never noticed a neighbor relationship is established to write it to.
And we should see something similar here.
Show IP IP neighbor neighbor relationship is established to route one show IP route.
Notice Rotto one has 1 9 2 1 6 8 1.0 directly connected on first.
Ethan It's 0 0 and 1 9 2 1 6 8 1 128 directly connected to cereal to slash zero.
Those are the two subnets.
It's also learnt about network 1 9 2 1 6 8 1 64 from 1 2 1 6 8 1 130.
In other words to in the same way Rodda 2 has 1 9 2 1 6 8 1 64 directly connected to foster.
Ethan it 0 0 and 1 on 2 1 6 8 1 128 is directly connected to cereal to slushes 0.
The Serrato has learnt about a network through choppy from 1 to 1 6 8 1 1:29.
In other words a 1 and it's learnt about network 1 2 1 6 8 1.0 so wrought at this point should be able
to ping PC 3 and PC for the pings succeed.
Now if you remember PCs 3 was allocated the IP address and we can confirm that by using the command
ifconfig Ethan at 0 is the IP address of PC 3 PC for RDF config.
Eath 0.
There's the IP address of PC for so rodder one is able to ping both the PCs now can PC one ping those
PCs so it can be paying one on to one success said one sixty five.
Yes we can.
And 66 Yes we can.
Let's trace 2 1 9 2 1 6 8 165.
Notice the trace goes to 1 2 1 6 8 1.
62 Rato 1.
Then it goes to 1 9 2 1 6 8 1 130 which is routed to the serial subnet and then it goes to 1 9 2 1 6
8 165 which is PC 3.
Be careful.
These are separate subnets.
These hosts are in different subnets so that was an example of subsetting.
We took a network we created subnets we worked up to the subnet address first host address last host
address and broadcast the address and we configured the network accordingly and then we tested that
it worked.
That was a simple example of a practical implementation of subsetting but it's really important that
you know how to subnet.
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I wish you all the very best.