Network Address Translation (NAT) explained | Static and Dynamic using Pools CCNA 200-301

Welcome to Network Engineer Pro. I’m Rafael, CCIE 64356.

I’m working on ton of content (videos, labs and more) to help you learn networking. If you want to stay up to date on what I’m working on and be the first to know then head to my website where you can sign up and get notified:
➤ https://www.networkengineerpro.com/

You can also follow me on Facebook:
➤ https://www.facebook.com/NetworkEngineerPro

Amazon affiliate links to recommended reading material

The CCNA 200-301 Official Cert Guide Volume 1
➤ https://amzn.to/3AWwjXh

The CCNA 200-301 Official Cert Guide Volume 2
➤ https://amzn.to/3wv81QQ

For those of you who want to take your studies to the CCIE level, here are the first two books(of many) you should get your hands on.

Routing TCP/IP, Volume 1
➤ https://amzn.to/3ARnVZj

Routing TCP/IP, Volume 2
➤ https://amzn.to/3k8wfxB

————————————————————————————————————–

In this video I wanted to cover NAT theory, so what the heck is it ?

At the most basic level, Network Address Translation (NAT) lets us translate one set of IP addresses, to another. So like a private address to a public address or maybe even a private address to a private address. The original purpose of NAT was to use it to slow the consumption of IPv4 addresses.

IPv4 has about 4.2 billion addresses available and with the rapid growth of the internet in the late 80’s and 90’s it was realized that yea were probably going to run out. Right now there is almost 8 billion people in the world, so not enough for every one person to have a device with a unique ip address.

That impending doom of IP address exhaustion being anticipated,
was the main reason for creating things like CIDR, classless inter domain routing, and NAT network address translation back in the 90’s.

And its a good thing they did, because in 2011 the Internet assigned numbers authority(IANA) which is the the organization that oversees and manages global address spaces, allocated the last /8 address block.

IPv6 is another option to address ipv4 address exhaustion, but that’s a topic for another day.

Here are the 3 types of NAT.
Static, Dynamic with Pools and PAT (NAT overloading). Of these 3, only Static and Dynamic using Pools are on the current CCNA blue print and are the ones covered in this video. I will do a separate video for PAT.

Static NAT:
Static NAT is when you manually configure a 1 to 1 mapping. For example like a private RFC 1918 IP to a public globally routable IP. This requires one globally routable IP address for every inside host that wants to communicate out on the Internet.

Dynamic NAT using Pools:
With Dynamic NAT private IP’s are translated to public IP’s from a manually created pool of available public addresses. What’s great here is that you don’t have to configure those manual 1 to 1 mappings for each host like with static NAT. You configure the pool and other required config and boom, the router takes care of the translations dynamically. The down side is that just like static NAT, every inside host needs its own public IP. As long as the pool has IP’s available then they will get translated by the router.

PAT (Overload) * Not covered in current CCNA and it will be covered in it’s own video:
Port Address Transaction (PAT) or NAT Overload translates multiple private IP’s to one public globally routable IP. It does this by using different ports. This is most common NAT implementation.

NAT terms
Inside local address—The IP address assigned to a host on the inside network. This is the address configured as a parameter of the computer OS or received via dynamic address allocation protocols such as DHCP. This is the easiest one to remember. Think like the IP address assigned to a workstation inside our network like PC’1’s IP for example 192.168.1.1/24

Inside global address— This is a globally routable IP that PC1 was translated to so post NAT. It is globally routable, but still represents PC1 which lives on the inside.

Outside local address—The IP address of an outside host as it appears to the inside network.

Outside global address—The IP address assigned to a host on the outside network by the host owner. Like 8.8.8.8 for Google’s public DNS server.

#ccna #ccnp #ccie

Views : 917
network engineer

Source by Network Engineer Pro