Explanation

Box 1: 3
One virtual network for every tier
Box 2: 1
Only one subnet for each tier, to minimize the number of open ports.
Scenario: You have a public-facing application named App1. App1 is comprised of the following three tiers:
* A SQL database
* A web front end
* A processing middle tier
Each tier is comprised of five virtual machines. Users access the web front end by using HTTPS only.
Technical requirements:
* Move all the virtual machines for App1 to Azure.
* Minimize the number of open ports between the App1 tiers.