In this article I describe the inside and outside interface of router in networking. We know router connect different LAN and transfer the data packets from one LAN to another LAN. ACLs works on inside and outside interface of router. It is necessary to know the inside and outside interface of router to apply the ACLs. ACLs are used to provide network security from unauthorized access.
Network security is necessary to protect the own networking devices and clients from unauthorized access, destruction and malfunction etc. Internet is the main resource of security threats. We manage the network for protection from these threats. We can say network security is all about to protect our internet connected computers from virus and hackers. You can manage our network security by using some firewalls, router etc. We allow unauthorized access to unknown persons by compromising own network security.
There are many types of vulnerability in a network connected with internet. Hackers from all over the world always try to get information from any network. You can safe your network from these attacks by understanding some network security basic concepts and use the firewall in your network. Now a lots of devices transfers data over the internet over wired, wireless and cellular networks.
Network security protects the devices from unauthorized access and malfunction activities. Malfunction activities can modify or destroy the data. The major cause of data theft is frequently use of internet from mobile and computers. We share personal data on social sites and do financial transaction on internet. The data shared on internet is always on risk from hackers and attackers. To keep safe the data from unauthorized access network security is necessary. We can prevent the attacks on our devices by using the firewall in network security.
ACL stands for Access Control List. There are basically single inside and outside interface or router works for ACLs. Inside and Outside interface of router further divided in two types Local and Global. So we have four terms inside local, inside global, outside local and outside 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 interface or router above. The purpose of these four terms is to apply the ACLs on them for filtering the traffic. You can create the ACLs in router but ACLs works only on fix interfaces. So you have to identify which ACL is required for which interface. In later articles I explain the ACLs in brief.
In this article I described the inside and outside interface of a router. For any query or suggestion on this article you may contact us or drop a comment below. Your suggestions are always welcome by us.
