Internet Gateway - Definition

An internet gateway is a central interface that connects a local area network (LAN) to the internet. It enables devices within a private network to access external networks, whilst ensuring that data traffic is transmitted securely and in a controlled manner.

The main task of an internet gateway is to forward data packets between different networks. In doing so, it performs important functions such as routing, protocol translation and NAT (Network Address Translation). NAT enables multiple devices within a private network to access the internet via a single public IP address.

Internet gateways are used in various IT environments:

• Home networks: The router typically acts as an internet gateway by connecting the local network to the internet.
• Corporate networks: Here, gateways ensure a secure connection between internal systems and the internet, or between different sites.
• Cloud computing environments: In virtual networks, an internet gateway enables communication between cloud resources and the public internet.

In cloud infrastructures, an internet gateway is often highly available and horizontally scalable, enabling large volumes of data to be processed reliably. It typically supports both IPv4 and IPv6 traffic. For an internet gateway to function, it must be connected to a virtual network such as a VPC (Virtual Private Cloud). In addition, routing rules must be defined.