Introduction
In the pervious part, we established the end to end Layer 3 connectivity between on-premises and Azure virtual network. Any production grade setup will need the capability to reach the resource across network boundaries using fully qualified names. Using IP will work but it is not scalable. IP can change, it is cumbersome, exposes the resource to changes that happen in other peered networks. This is where Domain Name Server comes in, enabling resource discovery using fully qualified names. I’m not saying this is all that a DNS does, but to our setup this is the most critical aspect that DNS enables.
Before starting with DNS, I believe this is the ideal point to spend time refactoring the topology a bit.
Current topology and its limitations
As things stand our setup has a S2S established between single virtual networks - one each on on-premises and Azure. Although this works, it is not ideal for environments that have multiple workloads running with different access restrictions. It will become a maintenance headache with just a handful of workloads on either side.
Azure - transition to hub and spoke
On-premises - simulate hub and spoke
Summary