Azure service that creates secure, encrypted connections over the internet between your networks and Azure. Like setting up a secure tunnel through a public subway system - anyone can see the tunnel, but they can't see what's inside.
A small business uses VPN Gateway to securely connect their office network to Azure resources, allowing employees to access cloud applications safely.
All four services provide encrypted IPsec/IKE VPN tunnels over the public internet to connect on-premises networks (or other clouds) to a cloud virtual network (VPC/VNet). Azure VPN Gateway is deployed into a VNet and supports site-to-site, point-to-site, and VNet-to-VNet connections; the others offer comparable site-to-site capabilities with provider-specific options and limits.