This is one of multiple network address translation or not videos.
This is a troubleshooting video.
In this scenario you've been told that some hosts in the internal network are not able to connect to
the Internet.
In this genus three typology I've got four rods broader two and three are acting as PCs they have IP
routing disabled.
They have the default gateways configured as Router one router one is going to act as our network address
translation Rodda and Foy's going to act as Google.
So let's test the network can write a one paying the DNS server Subroto for pretending to be the Google
DNS server.
Yes it can.
What about router 3.
Doesn't look like it's able to ping.
Let's investigate.
So show IP wrought we can see that IP routing is disabled on those router but its default gateways configured
is 10 more than one.
What about on Route 2 rather 2 has the same configuration wrote it too.
Can ping 10 1 1 1 and can ping Google router 3 can paying 10 1 1 1.
We could trace to Google it gets to its default gateway 10 1 1 1 but then nothing happens.
So we have a timeout on brought a 1 so brought a one let's confirm the IP address I think firstly if
0 slash one has an IP address of 10 1 1 1 that's the inside of the network.
If 0 0 has an IP address of 8 8 8 2 5 4.
So let's do it debug on this router debug IP Nat a was able to pinged Google before and still can and
we can see the NAT translation taking place when Rotto three pings.
Google dot com we don't see any net translations.
Sure.
IP net translations.
So we see a net translation for Rodda too.
That's the IP address of rodded.
So show IP face brief will show us that so we can see the translation for rodded too.
But we don't see a net translation for Rodda 3.
What happens if we clear the natural translations.
So there are no net translations at the moment.
When I ping from router three to Google we suddenly see translations and the pings start succeeding
Ken brought it to Payne.
Google dot com
noticed router too can now no longer ping Google that come let's clear the net translations again.
Ratatouille is now able to pin Google dot com
but Raanta 3 is not
so it looks like when we clear the translations one device is able to connect to Google Sherburne
if 0 0 is correctly configured with an IP address and is configured as the outside interface.
If a zero slushed one has the correct insight IP address and is configured as the inside Knecht interface
OK.
Can you see the problem.
What's going on here.
I noticed when I clicked the next translation again
and then ping from Rodda three which wasn't able to ping previously the pings.
Now succeed.
Show IP match translation.
We now see a net translation 4 out of three so going back through the configuration and I'll scroll
down to the net config.
Can you see the problem OK.
Have a look at this IP not inside source.
The last one which is pointing to access list one that means that any IP address will be netted but
it's pointing to a poll called my poll the Nat Poole is configured with a starting IP address of 8 8
8 to 2 and an ending IP address of 8 8 8 to 2.
That means we've only put one IP address in the poll hence only one internal host can be netted at any
given time.
So let's remove this.
We are told that we can't remove it so let's clear the ARPANET translations.
Translations staw and trying to remove it again.
So remove now.
What we should do is add additional IP addresses to the poll so and from 2 to 20.
Previously it was from 8 8 8 0 2 2 8 8 8 to 2 but now it's going from 2 to 20.
So show run piping clewed that will show us that configuration so Ken rotas three paying Google yes
it can.
Ken Rodda to ping Google yes it can it took it a while to ping Google router 3 can ping Google and we
see the net translations for both of them.
Notice please that the one device is not to 2 8 8 8 or 3.
And the other one is netted to 8 today to today Touche so show IP net translation shows us that two
addresses in the pool have been used to show IP not statistics.
At the moment we have a six dynamic translations notice of polls shows us the list of IP addresses.
So we have a starting address of 8 8 today 8 2 and ending of 8 8 8 to 20.
They are 19 addresses in the pool and two have been allocated.
So this would be another good command to use Let's clear the net translation and remove the command
and I'll add it back with only a single IP address in the poll.
So show IP not translations no translations at the moment show IP that statistics notice we only have
one IP address in the pool.
So when rodders three pings
and we look at the statistics again notice 100 percent of the polies allocated.
So that's why I wrote it too.
He's not able to ping because the because the pool consists of a single IP address and it's already
been allocated.
So again be careful with your polls.
You need to allocate enough addresses to the poll so clear the net translations again.
All remove that poll configure it again with let's say from 2 to 25 to show IP not statistics.
We have 24 addresses in the poll in this range none have been allocated since some traffic from both
wrote to and registry.
So we can see that rodded is being Nottage and so is lot a three.
And now when we look at the statistics noticed 24 addresses are available to have been allocated.
So that was an example of how to troubleshoot network address translation on net Oakie found the video
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