What
is 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. This process is
usually done by routers or firewalls.
An
example will help you understand the concept:
Host
A request a web page from an Internet server. Because Host A uses private IP
addressing, the source address of the request has to be changed by the router
because private IP addresses are not routable on the Internet. Router R1
receives the request, changes the source IP address to its public IP address
and sends the packet to server S1. Server S1 receives the packet and replies to
router R1. Router R1 receives the packet, changes the destination IP addresses
to the private IP address of Host A and sends the packet to Host A.
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 intern
SoSSource:https://cutt.ly/jnalFQl