Which THREE components are required to implement a secure hybrid network with Azure using a site-to-site VPN?
A public IP address is required for the Azure VPN gateway to be reachable from the on-premises VPN device. This IP is assigned to the gateway's IPsec tunnel endpoint and must be a standard SKU public IP, which can be dynamic or static. Without this publicly routable address, the on-premises device cannot initiate or complete the IPsec connection, making it a mandatory component for a site-to-site VPN.
Why this answer
To implement a secure hybrid network with Azure using a site-to-site VPN, three components are required: a virtual network gateway (which provides the VPN termination), a local network gateway (which represents the on-premises network), and a public IP address (which is assigned to the virtual network gateway to enable communication over the internet). The VPN gateway (option C) is not a separate component; it is a type of virtual network gateway. An ExpressRoute circuit (option B) is for dedicated private connections, not VPN.
Exam trap
Candidates often confuse the virtual network gateway with the VPN gateway, thinking they are separate components, and may omit the public IP address. However, the virtual network gateway (option D) is the actual Azure resource, and the VPN gateway is a configuration type. Additionally, a public IP address is a required resource that must be created and assigned to the gateway.