- [Teacher] In this next lab,
we're going to configure dynamic NAT.
Let's run out to the Corp router and configure
dynamic NAT so my PC can get to the internet.
As you're aware, to perform dynamic NAT,
we're gonna create a pool.
So I'm gonna say ip nat pool Lammle.
It doesn't matter, the name.
It's case-sensitive, though.
And I'm gonna create a pool of addresses.
Now if you were in production, you'd have
to get these addresses from your ISP.
And so I have a start address and an ending address.
netmask 255.255.255.255/28 here, right?
Well there's another way you can type this,
doesn't matter which one.
prefix-length, and then you type in
the length of 28 either way.
So not one was better than the other.
So either way, netmask or prefix-length, your choice.
Now I've already marked my inside and outside interfaces,
but I've gotta do two other things so we can tell
which hosts can use this pool.
Right now, it's still a one-to-one translation
like static NAT, so we're not really gaining much
by doing dynamic NAT when creating a pool.
The first thing I wanna do is say
who can use the pool by using a simple standard
access-list 1 permit, the 10 network.
Okay, inverse mask.
So who can use it?
10.1.1.0, don't put another line in there,
no one else can use it but the 10 network.
Now one other command I need is the ip nat inside source
can use list 1 and get an address from pool Lammle.
That's all there is to it, three lines.
And then I have to mark my interfaces.
So the first line here,
let's see if I can see the whole thing, there it is,
ip nat pool, the name, starting and ending address,
and netmask or prefix-length, either way.
I do have my interfaces marked already
with the ip nat inside and outside.
I'm just not showing that to you.
But don't forget to do those,
those are a good test objective.
Let's run out to our PC now, and first thing we're gonna do
is ping 209.165.201.2, which is my internet.
I love this, and then I'm just gonna type in Internet,
and get to the internet.
That's awesome.
We'll leave that open and run out to Corp.
And we're gonna verify with a couple commands here.
show ip nat translations.
A very good command.
Now we can see that, again, I am not using the port numbers.
Don't get confused on this one.
They're just referencing them in
the NAT table of what you're using here.
So I used ICMP, if we're paying TCP for Telnet,
that's not how it's keeping track of my session.
The last line is my inside local and my inside global.
For every single user, I need another inside global.
Alright, one last command, show ip nat statistics.
This is a great command that gives me a summary,
so we can see it's almost a full page here.
Total active translations, three.
And it tells me the inside and outside interfaces,
so we get a summary of the configuration, look at this,
the access list, the pool, and how many were missed,
meaning that they got NAKed, or they couldn't,
they didn't have any room in the pool
or they didn't have a correct IP address.
So that's how you configure dynamic NAT and verify it
to show IP NAT translations, of course, and then also
start using your show ip nat statistics command.