What is an Azure site-to-site VPN?

A site-to-site VPN allows you to create a secure connection between your on-premises site and your virtual network. The solution uses industry standard IPsec VPN in Azure. For that reason it is interoperable with most VPN devices. You can refer to a list of known compatible devices and sample configurations in the Azure website. You can use this service to connect up to 10 on-premises sites and virtual networks to each other securely. Once a site-to-site VPN is setup you have IP level connectivity between your premises and virtual networks in Azure. This enables you to build truly hybrid applications in Azure. Use this service in cases where your cross-premises connectivity throughput is nominal (~ 100 Mbps).