What is NAT and How NAT works..?

In this tutorial, we are going to see about, How NAT works, Before Going to this tutorial, I recommend you to look into Private and Public Address.

What is NAT

• NAT – Network Address Translation
• It converts Private IP address to Public address and again back to Private Address
• NAT has to be done before your traffic reaches the internet.
• Private IP Address are not routable on the Internet

Types of NAT

• Static NAT
• Converts one Private IP to one Public IP (1:1 ratio)
• Dynamic NAT
• Converts a Private IP segment range to Public IP Segment (We need to get a Public IP Network segment from ISP, and not  a single Public IP)
• PAT
• Converts a Private IP segment to Single IP, and each Private IP is seperated by a port number when translating to Public IP )

How NAT Works ? 

• When PC tries to reach the a Server, it has the source as 192.168.1.1 and destination as 8.8.8.8 and forwards the packet to the concern destination
• When Server replies it with a source as 8.8.8.8 and destination as 192.168.1.1
• When this packet enters to the internet, it sees the Private IP as destination,
• and it discards the packet as Privarte IP's are not Routable.

• When NAT is configured, Private IP Address will be translated to a Public IP.
• It will be forwarded from the CE-Router with source as 1.1.1.1 and destination as 8.8.8.8
• When Server replies it with a source as 8.8.8.8 and destination as 1.1.1.1
• As it is a Public IP, it will routed in the Internet and forwarded to the CE-Router.
• CE-Router translates the Public IP 1.1.1.1 to 192.168.1.1 and keep source as 8.8.8.8 and 
• destination as 192.168.1.1 

That's it about NAT
If you have any questions, Kindly comment below

You can also look into my Video in English below:

You can also look into my Video in Tamil below: