As App1 is public-facing we need an incoming security rule, related to the access of the web servers.
Scenario: You have a public-facing application named App1. App1 is comprised of the following three tiers: a SQL database, a web front end, and a processing middle tier.
Each tier is comprised of five virtual machines. Users access the web front end by using HTTPS only.

By default, storage accounts accept connections from clients on any network. To limit access to selected networks, you must first change the default action.
Azure portal
1. Navigate to the storage account you want to secure.
2. Click on the settings menu called Firewalls and virtual networks.
3. To deny access by default, choose to allow access from 'Selected networks'. To allow traffic from all networks, choose to allow access from 'All networks'.
4. Click Save to apply your changes.
Grant access from a Virtual Network
Storage accounts can be configured to allow access only from specific Azure Virtual Networks.
By enabling a Service Endpoint for Azure Storage within the Virtual Network, traffic is ensured an optimal route to the Azure Storage service. The identities of the virtual network and the subnet are also transmitted with each request.
Reference:
https://docs.microsoft.com/en-us/azure/storage/common/storage-network-security

Topic 1, Litware, inc.
Existing Environment
The network contains an Active Directory forest named Litware.com. All domain controllers are configured as DNS servers and host the Litware.com DNS zone.
Litware has finance, human resources, sales, research, and information technology departments. Each department has an organizational unit (OU) that contains all the accounts of that respective department. All the user accounts have the department attribute set to their respective department. New users are added frequently.
Litware.com contains a user named User1.
All the offices connect by using private links.
Litware has data centers in the Montreal and Seattle offices. Each data center has a firewall that can be configured as a VPN device.
All infrastructure servers are virtualized. The virtualization environment contains the servers in the following table.

Litware uses two web applications named App1 and App2. Each instance on each web application requires 1GB of memory.
The Azure subscription contains the resources in the following table.

The network security team implements several network security groups (NSGs).
Planned Changes
Litware plans to implement the following changes:
* Deploy Azure ExpressRoute to the Montreal office.
* Migrate the virtual machines hosted on Server1 and Server2 to Azure.
* Synchronize on-premises Active Directory to Azure Active Directory (Azure AD).
* Migrate App1 and App2 to two Azure web apps named webApp1 and WebApp2.
Technical Requirements
Litware must meet the following technical requirements:
* Ensure that WebApp1 can adjust the number of instances automatically based on the load and can scale up to five instance*.
* Ensure that VM3 can establish outbound connections over TCP port 8080 to the applications servers in the Montreal office.
* Ensure that routing information is exchanged automatically between Azure and the routers in the Montreal office.
* Enable Azure Multi-Factor Authentication (MFA) for the users in the finance department only.
* Ensure that webapp2.azurewebsites.net can be accessed by using the name app2.Litware.com.
* Connect the New Your office to VNet1 over the Internet by using an encrypted connection.
* Create a workflow to send an email message when the settings of VM4 are modified.
* Create a custom Azure role named Role1 that is based on the Reader role.
* Minimize costs whenever possible.