Good day everybody. I not too long ago got here throughout the subject of NAT and, this felt so attention-grabbing so I needed to share what NAT is and the way it works. That is for understanding networking on Azure. After all, we’re simply within the cloud device, however it’s good to know what occurs below the hood and it’ll assist whenever you take care of the networking half in Azure.
So what we shall be discussing on this submit is,
- What’s NAT
- How NAT got here into the image and a bit historical past
- How NAT works
- Forms of NAT
What’s Community Tackle Translation (NAT)
NAT is used to allow a number of hosts on a non-public community to hook up with the Web utilizing a single public IP tackle or we are able to say that the essential concept of NAT is to permit a number of gadgets to entry the Web via a single public tackle.
So principally, NAT helps a non-public community to speak with the general public community(Web).
How NAT got here into the image and a bit historical past
Again in 1994, there was an issue with IPV4 and the issue was the IP tackle was allotted based mostly on the category. Class A tackle was given to large firms, smaller firms got class B and smaller ones acquired a category C tackle, and so forth and, the principle drawback with this technique was that thousands and thousands of sophistication A addresses had been wasted, lots of the class B tackle had been wasted, whereas, the variety of addresses accessible in school C is so small that it can not cater to the wants of organizations.
How NAT works
Community tackle translation between a non-public community and the Web
So if we see within the above image there’s a host linked to a non-public community, a router most probably be configured to make use of NAT and, a server linked to the web. If we wish to ship a message to the server from an inside system that’s linked to a non-public community with the supply tackle 10.0.0.1 and vacation spot tackle 200.100.10.1
Now after we ship this message out, the message will simply be transferred to the server as a result of our router seems to be for the vacation spot tackle which is 200.100.10.1
However what occurs when the server responds? Let’s discover out. When the server desires to reply and now vacation spot IP shall be 10.0.0.10 and supply IP shall be 200.100.10.1, now when the server responds, we all know the non-public is tackle shouldn’t be routable and the packet will get rejected and thrown away.
Right here comes the usage of NAT, when the server despatched the message to the router which shall be configured to make use of NAT, it takes supply IP (10.0.0.1) and shops it in a desk (also called NAT desk) and replaces it with public IP (150.150.0.1).
Now, if we ship any message from non-public IP to the web it’s going to attain the server, and when the server responds vacation spot IP shall be 150.150.0.1 which is public and factors to our router, as soon as the router receives the message it seems to be within the NAT desk and it removes the general public IP 150.150.0.1 and replaces it with non-public tackle 10.0.0.10 and replaces it with non-public tackle 10.0.0.10 and forwards the message again to the system.
Forms of NAT
- Static NAT
A single non-public IP tackle is mapped with a public IP tackle and is mostly used for Website hosting.
- Dynamic NAT
A non-public IP tackle is translated right into a public IP tackle from a pool of public IP addresses.
- Port Tackle Translation (PAT)
Many non-public IP addresses will be translated to a single registered IP tackle. Port numbers are used to differentiate the visitors.
That’s it, I hope it helps you ultimately.
Keep residence, keep protected, and glad studying.
