Chapter 8
One potential solution to the MegaCorp Inc. requirements would be to use an ExpressRoute connection into Azure as this helps provide a stable but resilient connection.
To control internet traffic from solutions built in Azure, Azure Firewall could be built on a central VNET that all other VNETs will be peered to. That VNET can also contain the ExpressRoute's gateway VNET. In other words, a hub-spoke model will be used.
Each peered VNET will have two custom routes set up. One route will send traffic for on-premises IP ranges to the ExpressRoute gateway subnet and the other route will send other traffic to the central firewall's IP address.
NSGs will be set to allow outbound HTTPS and HTTP traffic to the firewall VNET and standard ports for DNS resolution to on-premises DNS servers. VNETs will be set up to use on-premises DNS servers as the primary servers with the Azure DNS (168.63.129.16) as the secondary.