Gateway: Gateway is used to connect LAN (Local Area Network) to the internet. It is also used to control the information which will be delivered between the connected computer systems. Usually a router is used as a device for a gateway. A phone line is also used along with the router to connect to the internet.
Here are the features of a gateway:
1) NAT (Network Address Translation): The primary purpose of a gateway is to perform network address translation. In this process, a gateway takes the packets from LAN and removes the private IP address of LAN and adds the ISP provided IP address and then the packets are sent out in the Internet. Thus, packets are sent to the internet from the gateway and no information of individual computers are passed along.
2) Control of information: Gateway is also used for controlling which information has to go out and which has to come in.
3) Log information: The delivery of packets is logged in the gateway and you can check which individual computer has accessed which information.
4) Caching: Gateway puts the information in the cache so that if the same information is accessed, it will be accessed from the cache and not directly from the internet. That way, information can be accessed swiftly.