You can use either a CNAME record or an A record to map a custom DNS name to App Service. You should use CNAME records for all custom DNS names except root domains (for example, contoso.com). For root domains, use A records. Reference: https://docs.microsoft.com/en-us/Azure/app-service/app-service-web- tutorial-custom-domain

Explanation:

https://learn.microsoft.com/en-us/azure/network-watcher/network-watcher-monitoring-overview#monitoring The connection monitor capability monitors communication at a regular interval and informs you of reachability, latency, and network topology changes between the VM and the endpoint.
Connection monitor also provides the minimum, average, and maximum latency observed over time. After learning the latency for a connection, you may find that you can decrease the latency by moving your Azure resources to different Azure regions.

Explanation:
Box 1: 5
A public and a private IP address can be assigned to a single network interface.
Box 2: 1
You can associate zero, or one, network security group to each virtual network subnet and network interface in a virtual machine. The same network security group can be associated to as many subnets and network interfaces as you choose.

Reference:
https://docs.microsoft.com/en-us/azure/virtual-network/virtual-network-network-interface-addresses