- [Instructor] Basically dynamic NAT really means
we a have a pool of addresses that we'll use
to provide real IP addresses
to a group of users on the inside.
Because we don't use port numbers,
we must have real IP addresses for every user who's trying
to get outside the local network simultaneously.
This doesn't give us any value over static NAT
other than we don't have
to configure every line for every user.
Let's go ahead and take a look at an example here.
First thing we wanna do
is make sure our interface's markings are done.
That is our number one step.
The next command we wanna look at
with configuring dynamic NAT,
is our IP NAT inside source list one as our access list
that says who could use my pool.
And the name of the pool is case-sensitive.
We must understand access list to configure dynamic NAT.
So now number two, we'll make sure who can use the pool.
Number three, is to verify our access list.
Access list one.
Notice I'm just using simple standard access list here.
Permit 10.1.1.0 network.
Well that's my IP NAT inside address isn't it?
And if I had multiple inside interfaces,
I would have to permit each one with my access list.
OK The next thing we wanna do, the fourth thing,
is create a pool,
IP NAT pool,
notice the name is case-sensitive,
and this is my pool, 209.165.201.3
to 201.14.
Now I can use the either the netmask 255.255.255.240 command
or type in prefix-length 28.
That doesn't really save me anything,
it would have been nice if we could've
just typed in "/28", right?
This is a very simple configuration.
It is a little bit more complex than static NAT,
but it's really not that bad.
You have four steps instead of just a couple.
So our interfaces say who can use the pool,
and then create your access list,
and then create your pool.
So how do I verify this once I'm done?
Well pretty much the same thing,
show IP NAT translations.
Notice this, I have my inside local and my inside global.
Nothing more to it, I would have to have one for each
and every host that's going out.
I could also use something called
the show IP NAT statistics command.
And this is going to show me
some pretty good information about it.
It gives me an overview of my configuration.
So for example, it shows who my outside interface is
and my inside interface is in this example.
As well as my active translations and misses and so on.
OK so that's how easy it is to configure dynamic NAT,
let's churn out and give it a try.