This is one of multiple videos discussing that or network address translation in the video we are troubleshooting
a next issue.
We've been told that hosts on the inside network in other words these hosts which are being represented
by one wrote a four and wrote a five I'm not able to ping 8 8 8 8 which is a Google DNS server.
And in this example that's being represented by router 3.
So we have the inside and the outside network router.
Two in this topology is on next to Rodda So lets connect to of one which is acting as Host 1 and see
if it can ping 8 8 8 8 getting an unreachable message in the output here.
Let's have a look at the writing table.
The Shradha has a default gateway configured as 10 datt 1 to 1 2 2 5 4 that is wrote 2 in the typology
which is on that Rodda Serrato one acting as host one is able to get to the NAT router but it doesn't
look like it's able to get to the Google Rodda.
So you can see in the output here it's reached 10 1 1 2 5 4.
But it doesn't look like it can get any further.
Now just speed things up.
I'm going to use the no IP domain lookup command.
And then let's do that trace again.
So you can see it gets to default gateway but can't get any further than that.
Let's have a look at the default gateway and see what's happening with the net translations.
So this is rodded to show IP not translations.
There are no net translations at the moment.
Show IP not statistics.
So looking at the statistics we can see that they have been translations in the past.
Outside interfaces.
Gigabit is 0 1 which is this interface facing the Rodda acting as Google inside interfaces or gigabit
to 0 0 0 2 and 0 3.
In other words these interfaces over here a dynamic mapping has been configured for inside source address
translation.
We've got a access list pointing to a net pool called Nat Poole.
Can any of the other internal Rajahs ping Google.
So this is Route for all so getting unreachable to a debug IP not on route to we see a problem here
saying that NAT translation failed dropping the packet.
So we getting a dropped packet from 10 1 to 2
which is this router Let's have a look at Route one again.
So this product couldn't trace to Google.
Let's see what happens here.
We also are getting a NAT translation failure.
So let's have a look at the configuration gigabit 0 one is configured with this IP address and it's
configured as the outside address show run interface geek if it's 0 0 as an example.
It's configured with this IP address and it's configured as the inside not to address show run piping
Plude Nat.
So these are the statements on the interfaces telling us which interfaces are inside and outside.
If I do a show run pipe include access.
Can you see the problem.
OK so I notice the statement IP Nat inside source list 1 Paul Knecht.
Paul in other words we are saying that any traffic matching access list one which is permitting anything
will be netted according to this Nat Poole called Nat Poole.
But notice your IP Nat Poole Nat pole instead of a NAT poll is being used.
So everything else looks good except we've got a spelling mistake on the Nat Poole name.
So let's fix that.
No no.
Remove this command.
So no IP net Poole.
And then I'll edit that to make it correct.
So at the extra O.
So show run piping clewed not this Nat Poole reference by the IP that statement now exists in the configuration.
So let's try to do that ping again.
Ping succeeds and notice we can see that 10 1 1 1 which is this Rodda was nattered 2 8 2 8 8 8 to 10
which is the first IP address in the net pool for traffic going to 8 8 8 8 8.
And then when the return traffic came back the address was invited back to the internal address of the
router show IP Nat translation.
Shows us that.
So inside a local address is being netted to the inside global address the outside addresses not being
nattered So host one can ping Google and we see the NAT translation taking place host for can also ping
Google but come.
And we've also got another host to host five if you like.
Well Rodda five acting as our third host.
Can it ping Google yes it can.
So that was an example of how to troubleshoot.
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