What is Network Address Translation (NAT) ? 

NAT (Network Address Translation) is a process of changing the source and destination IP addresses and ports. Address translation reduces the need for IPv4 public addresses and hides private network address ranges. The process is usually done by routers or firewalls.

How does it work?

NAT allows a single device, such as a router, to act as an agent between the Internet (or public network) and a local network (or private network), which means that only a single unique IP address is required to represent an entire group of computers to anything outside their network.

There are three types of address translation:

1. Static NAT – translates one private IP address to a public one. The public IP address is always the same.
2. Dynamic NAT – private IP addresses are mapped to the pool of public IP addresses.
3. Port Address Translation (PAT)– one public IP address is used for all internal devices, but a different port is assigned to each private IP address. Also known as NAT Overload.