In this article I describe the inside and outside network of router in networking. NAT Network Address Translation defined in router to identify the different devices for different network traffic. NAT Network Address Translation is a method to allow multiple devices to access internet on a single public IP address. To access internet by a device required an unique address known as public IP address.
We know the IP addresses are limited and it is not possible to allot each device a unique IP address. To resolve this problem private IP address used with NAT Network Address Translation. Almost organisations used single Public IP address and allow their multiple users to access internet. This facility provided by NAT Network Address Translation.
The translation of private IP address to a public address done by NAT Network Address Translation. For translation inside local IP address converted to inside Global address . In simple words we can say NAT Network Address Translation allow the local hosts to access internet with single public IP address. Various web services accessible on particular port numbers like FTP on 21. These port numbers of various services helps to access the internet by local hosts. NAT Network Address Translation works on Network layer of OSI or TCP/IP model.
The main advantage of NAT is conservation of IP addresses. NAT save a lots of number of IP addresses. IP addresses are limited and devices on internet are more than them. A privacy level increased by NAT as the IP address of device will be hidden behind the public IP address. Changing of ISP doesn’t required any changes in local network. No compromise with speed of network by using the NAT. No need of reassigning local IP addresses in case of network evolves.
Inside and Outside network terms frequently used in NAT process. Inside refers as local address and outside refers as remote network. Before NAT translation the address is known as local. After NAT translation the address is known as Global address. So the inside and outside network address defines as inside local, inside global, outside global and outside local address. A user generally know the inside network addresses. If you are working on internet it is not necessary to know the outside network addresses.
We know router connect different LAN and transfer the data packets from one LAN to another LAN. NAT translation works on inside and outside interface of router. It is necessary to know the inside and outside interface of router for NAT translation. There are basically single inside and outside interface of router works for Network address translation. Inside and Outside interface of router further divided in two types Local and Global. In this article I brief all four types of interfaces of router. Below image describe the four terms of inside and outside interface of router.
A router works like an intermediate for LAN and WAN. Each router have a gateway for LAN which is responsible to take out the traffic from LAN to WAN and vice versa. So we have two interfaces of every router one is connected with LAN and one is connected with WAN. These two interfaces are known as Local and Global. It is depends on your position where are you lying in the network. See the image below. There are two different LAN connected with each other via two different routers. I explain all four terms from each LAN for better understanding of inside and outside interface of router.
Inside Local interface of router
Inside Local interface is known as the gateway of a LAN. In above image for LAN 1 the Inside Local is the IP address of interface A of router 1. Similarly the inside local for LAN 2 is the IP address of interface D of router 2. We can say the inside local for LAN 1 is 192.168.1.1. The inside local for LAN 2 is 192.168.2.1.
Inside Global interface of router
Inside Global interface is known as the WAN interface of router for a LAN. In above image for LAN 1 the Inside Global is the IP address of interface B of router 1. Similarly the inside global for LAN 2 is the IP address of interface C of router 2. We can say the inside global for LAN 1 is 10.10.10.1. The inside global for LAN 2 is 10.10.10.2.
Outside local interface of router
Outside Local interface is known as the gateway interface of remote LAN. In above image for LAN 1 the Outside Local is the IP address of interface D of router 2. Similarly the Outside Local for LAN 2 is the IP address of interface A of router 1. We can say the outside local for LAN 1 is 192.168.2.1. The outside local for LAN 2 is 192.168.1.1.
Outside Global interface of router
Outside Global interface is known as the WAN interface of remote router. In above image for LAN1 the outside global is the IP address of interface C or router 2. Similarly the Outside Global for LAN 2 is the IP address of interface B of router 1. We can say the outside global for LAN 1 is 10.10.10.2. The outside global for LAN 2 is 10.10.10.1.
I explained the inside and outside network of router above. The purpose of these four terms is to understanding the inside and outside network for NAT translation. I hope you found the inside and outside network of router article helpful. For any query or suggestion on this article you may contact us or drop a comment below.
