What is NAT?
Network Address Translation.
In order to understand NAT, we first need to understand private address and public address.
A private network allows organizations to connect with different departments without using internet. There is no requirement of internet in private network.
All the devices connected to each other, without internet, forms a private network.
It can vary in between 192.168.0.0 – 192.168.255.255 (65,536 IP addresses) 172.16.0.0 – 172.31.255.255 (1,048,576 IP addresses) 10.0.0.0 – 10.255.255.255 (16,777,216 IP addresses)
So, a private address is the local IP assigned to the devices inside the private network.
A public address is assigned to a device when it connects to the internet.
There are fewer than 4.3 billion addresses available under IPv4 address pool. During the late 1980s, IPv4 address exhaustion was anticipated.
IPv4 address exhaustion is the depletion of the pool of unallocated IPv4 addresses. That’s when NAT came in action.
NAT basically assigns a single public address to all the devices inside the private network. This means that all the devices in the private network have same public ip address. Even a large organization having lots of devices, can connect to internet on a single public address.
