- [Instructor] So there's three different types of NAT.
Static NAT, dynamic NAT,
and PAT, or Port Address Translation,
which is the most popular today
and the reason that we have not run out of IPV4 addresses.
So with static NAT, we have a one-to-one address mapping.
Pretty impossible just to use this today.
Absolutely impossible, not pretty impossible,
absolutely impossible.
For dynamic NAT, we have many-to-many,
it's still really a one-to-one,
but it allows us to create a pool.
And this pool can have many addresses
that users can use to get out onto the internet
and then put it back in the pool when you're done.
Again, not usable for today's networks.
Port address translation is a many-to-one address mapping.
So theoretically,
I can use up to 65,000 internal hosts
using one global address
to get out onto the internet.
Let's go ahead and take a look
at the commands to configure static NAT,
then we'll go ahead and run out and do it.
First off, we're gonna go ahead and put our IP addresses
that we use underneath our interfaces.
This is step number one.
Your interface markings.
You tell NAT which are inside and outside interfaces.
This is your number one troubleshooting spot,
and your number one configuration spot.
Once you do that with static NAT,
it's pretty simple.
It's one-to-one, I have to have a real internet IP address
for each and every user inside my network.
So in this case here,
the IP NAT inside source command
identifies which IP addresses will be translated.
So this configures a static translation
between the inside local address of 10.1.1.2
and the outside global address of 209.165.201.5.
So just remember about static NAT,
very simple, very few commands.
Check your interfaces.
Put in the IP NAT inside source static command
for each host that wants to get onto the internet.
And just remember, they're always present in the NAT table.
So we statically are putting them in the NAT table.
Nothing dynamic about this.
And one of the benefits that you can think about
with static NAT for CCNA
is that you can allow connections from the outside,
so we can reverse this IP NAT outside source.
Now you would never do that in production anymore,
that's why we created VPNs.
So before we run out and configure it,
let's take a look
at how we're gonna verify our configuration.
Pretty simple.
We're gonna use the shop IP NAT translations command.
And notice this configuration that shows
my inside local and my inside global.
Notice it's a one-to-one translation and if I had 10 users,
I'd have to have 10 entries in this translations table.
So now let's run out and configure this,
and verify static NAT.