what is NAT? NAT is stands for NetworkAddress Translation and it is used to convert a private IP address into apublic and a public IP address into a private but the question is why do weneed to convert the private IP address into public or a public IP address intoprivate I am going to explain you everything including this I will alsoexplain you what are the advantages and disadvantages of NAT in a computernetwork.
Tech let's the tech begin guys basically we use NAT because ofthe shortage of IP address. IP version 4 is a 32-bit address and it has around4.2 billion of IP address but the population of our beautiful world isaround 7.2 billion according to 2017 and most of the users are also usingmultiple devices such as a smartphone laptop desktop tablet etc and foraccessing Internet all this device need I P address right.
So, 4.2 billion of IPaddress is not sufficient for more than 7.2 billion of users so for this reasonwe are using NAT. NAT is used to convert a private IP address into the public anda public IP address into the private so how this entire concept of NAT that isNetwork Address Translation works let's find out.
let's take an example there arefour computers in a network but only one Internet connection. Now the question ishow it is possible for these four computers to access this single internetconnection at the same time it is possible with the help of NATthat is Network Address Translation .
Here all the four computers areassigned with the private IP address such as 10.0.0.1 ,10.0.0.2, 10.0.0.3 & 10.0.0.4and this private IP address are not rootable in internet It means the sameaddress can be used unlimited number of times on different network.
I havecreated a separate post on what is private and public IP address if youwant to know more about this follow the link given in the description sectionbelow now let's concentrate on NAT whenever the PC 1 assign with theprivate IP address 10.0.0.1 wants to access internet it will first send a request to therouter, your router is going to convert this private IP address into publicand add a unique port number to it and save this information to its NATForwarding Table after that it will forward the request to the internet.
Solike this with the help of port number it will be easy for the Router toremember which device has requested for the packet now the time your routerreceives the reply from the internet it is going to check its NAT Forwarding Tableand convert this public and P across into private and send the packet to therequested at PC.
This is how the entire concept of NAT works. Let's take ananother example so that it will be easy for you to understand. The time PC 2assigned with the private IP address 10.0.0.2 wants to want to access theinternet it will first send a request to the router your router is going toconvert this private IP address into public and add a unique port number toit and save this information to its NAT Forwarding Table.
After that it willforward the request to the internet so like this it will be easy for your router toremember which device has requested for the packet now the time your routerreceives a reply from the internet it is going to check its NAT forwarding tableand convert this public IP address into private and send the packet to the requestat PC so this is the basic concept of NAT that is Network Address Translation.
Do you know one interesting facts about NAT? For Internet your entire device inthe private network is look-alikes one single device this is because publicnetwork only knows this single public IP address of your network not the privateIP address of devices in a network like this NAT helpsyou to hide the real IP address of your network from the external user and actas a firewall.
So guys this is the basic concept of NAT. Now, let's find out whatare the advantages and disadvantages of using NAT in a computer network.