Network address translation
NAT is the method of translation of private IP address into public IP address. In order to communicate with internet we must have registered public IP address.
Address translation was originally developed to solve two problems:
- To handle a shortage of IPv6 addresses
- Hide network addressing schemes.
Private address range
There are certain addresses in each class of IP address that are reserved for private networks. These addresses are called private addresses.
Class A 10.0.0.0 TO 10.255.255.255
Class B 172.16.0.0 TO 172.31.255.255
Class C 192.168.0.0 TO 192.168.255.255
Types of NAT :-
Port address Translation (PAT)
Static NAT- one to one mapping done manually for every private IP need on registered IP address (one to one)
Dynamic NAT- one to one mapping done automatically For every private IP needs one registered IP address (one to one)
Port address translation ( Dynamic NAT Overload )- Allows thousands of users connect to the internet using only one real global IP address. Maps many to one by suing different ports. PAT is the real reasons we are haven’t run out of valid IP address on the internet.