GRE (Generic Routing Encapsulation)

GRE (Generic Routing Encapsulation) is a tunneling protocol used in networking to transmit various network layer protocols over an existing IP network. It creates a virtual "pipe" between two points, encapsulating data packets so they can travel securely and efficiently across the internet or other networks, even if the underlying network doesn't natively support those protocols. Think of it as a secure, customizable delivery service that packages different types of information together, allowing diverse data to reach remote locations reliably. GRE is commonly used to connect different networks securely over long distances.