A VNet-to-VNet connection is a simple way to connect multiple VNets together. Connecting a virtual network to another virtual network is similar to creating a site-to-site IPSec connection to an on-premises environment. Both the connection types use the Azure virtual private network (VPN) gateway. The VPN gateway provides a secure IPSec/IKE tunnel, and each side of the connection communicates in the same way. The difference is in the way the local network gateway is configured.
The local network gateway address space is automatically created and populated when a VNet-to-VNet connection is created. When the address space of one VNet is updated, this will result in the other VNet automatically routing the traffic to the updated address space....
