AZ-700 Designing and Implementing Microsoft Azure Networking Solutions Questions and Answers

Here are the steps and explanations for ensuring that connections to the storage34280945 storage account can be made by using an IP address in the 10.1.1.0/24 range and the name stor-age34280945.pnvatelinlcblob.core.windows.net:

To allow access from a specific IP address range, you need to configure the Azure Storage firewall and virtual network settings for your storage account. You can do this in the Azure portal by selecting your storage account and then selecting Networking under Settings1.

On the Networking page, select Firewalls and virtual networks, and then select Selected networks under Allow access from1. This will block all access to your storage account except from the networks or resources that you specify.

Under Firewall, select Add rule, and then enter 10.1.1.0/24 as the IP address or range. You can also enter an optional rule name and description1. This will allow access from any IP address in the 10.1.1.0/24 range.

Select Save to apply your changes1.

To map a custom domain name to your storage account, you need to create a CNAME record with your domain provider that points to your storage account endpoint2. A CNAME record is a type of DNS record that maps a source domain name to a destination domain name.

Sign in to your domain registrar’s website, and then go to the page for managing DNS settings2.

Create a CNAME record with the following information2:

Source domain name: stor-age34280945.pnvatelinlcblob.core.windows.net

Destination domain name: stor-age34280945.pnvatelinlcblob.core.windows.net

Save your changes and wait for the DNS propagation to take effect2.

To register the custom domain name with Azure, you need to go back to the Azure portal and select your storage account. Then select Custom domain under Blob service2.

On the Custom domain page, enter stor-age34280945.pnvatelinlcblob.core.windows.net as the custom domain name and select Save2.

To deploy Azure virtual machines to the France Central region and ensure they are in a network segment with an IP address range of 10.5.1.0/24, follow these steps:

Step-by-Step Solution

Step 1: Create a Virtual Network in France Central

Navigate to the Azure Portal.

Search for “Virtual networks” in the search bar and select it.

Click on “Create”.

Enter the following details:

Subscription: Select your subscription.

Resource Group: Select an existing resource group or create a new one.

Name: Enter a name for the virtual network (e.g., VNet-FranceCentral).

Region: Select France Central.

Click on “Next: IP Addresses”.

Step 2: Configure the Address Space and Subnet

In the IP Addresses tab, enter the address space as 10.5.1.0/24.

Click on “Add subnet”.

Enter the following details:

Subnet name: Enter a name for the subnet (e.g., Subnet-1).

Subnet address range: Enter 10.5.1.0/24.

Click on “Add”.

Click on “Review + create” and then “Create”.

Step 3: Deploy Virtual Machines to the Virtual Network

Navigate to the Azure Portal.

Search for “Virtual machines” in the search bar and select it.

Click on “Create” and then “Azure virtual machine”.

Enter the following details:

Subscription: Select your subscription.

Resource Group: Select the same resource group used for the virtual network.

Virtual machine name: Enter a name for the VM.

Region: Select France Central.

Image: Select the desired OS image.

Size: Select the appropriate VM size.

Click on “Next: Disks”, configure the disks as needed, and then click on “Next: Networking”.

In the Networking tab, select the virtual network (VNet-FranceCentral) and subnet (Subnet-1) created earlier.

Complete the remaining configuration steps and click on “Review + create” and then “Create”.

Explanation

Virtual Network: A virtual network in Azure allows you to create a logically isolated network that can host your Azure resources.

Address Space: The address space 10.5.1.0/24 ensures that the VMs are in a specific network segment.

Subnet: Subnets allow you to segment the virtual network into smaller, manageable sections.

Region: Deploying the virtual network and VMs in the France Central region ensures that the resources are physically located in that region.

By following these steps, you can ensure that your Azure virtual machines in the France Central region are deployed within the specified IP address range of 10.5.1.0/24.

Here are the steps and explanations for creating a policy that can be linked to the planned application gateway and block connections from IP addresses in the 131.107.150.0/24 range:

To create a policy, you need to go to the Azure portal and select Create a resource. Search for WAF, select Web Application Firewall, then select Create1.

On the Create a WAF policy page, Basics tab, enter or select the following information and accept the defaults for the remaining settings:

Policy for: Regional WAF (Application Gateway)

Subscription: Select your subscription name

Resource group: Select your resource group

Policy name: Type a unique name for your WAF policy

On the Custom rules tab, select Add a rule to create a custom rule that blocks connections from IP addresses in the 131.107.150.0/24 range2. Enter or select the following information for the custom rule:

Rule name: Type a unique name for your custom rule

Priority: Type a number that indicates the order of evaluation for this rule

Rule type: Select Match rule

Match variable: Select RemoteAddr

Operator: Select IPMatch

Match values: Type 131.107.150.0/24

Action: Select Block

On the Review + create tab, review your settings and select Create to create your WAF policy1.

To link your policy to the planned application gateway, you need to go to the Application Gateway service in the Azure portal and select your application gateway3.

On the Web application firewall tab, select your WAF policy from the drop-down list and select Save

To deploy a firewall to subnetl-2, you need to create a network virtual appliance (NVA) in the same virtual network as subnetl-2. An NVA is a virtual machine that performs network functions, such as firewall, routing, or load balancing1.

To create an NVA, you need to create a virtual machine in the Azure portal and select an image that has the firewall software installed. You can choose from the Azure Marketplace or upload your own image2.

To assign the IP address of 10.1.2.4 to the NVA, you need to create a static private IP address for the network interface of the virtual machine. You can do this in the IP configurations settings of the network interface3.

To ensure that traffic from subnetl-1 to the IP address range of 192.168.10.0/24 is routed through the NVA, you need to create a user-defined route (UDR) table and associate it with subnetl-1. A UDR table allows you to override the default routing behavior of Azure and specify custom routes for your subnets4.

To create a UDR table, you need to go to the Route tables service in the Azure portal and select + Create. You can give a name and a resource group for the route table5.

To create a custom route, you need to select Routes in the route table and select + Add. You can enter the following information for the route5:

Destination: 192.168.10.0/24

Next hop type: Virtual appliance

Next hop address: 10.1.2.4

To associate the route table with subnetl-1, you need to select Subnets in the route table and select + Associate. You can select the virtual network and subnet that you want to associate with the route table5.

Here are the steps and explanations for ensuring that hosts on VNET2 can access hosts on both VNET1 and VNET3, but hosts on VNET1 and VNET3 cannot communicate through VNET2:

To connect different virtual networks in Azure, you need to use virtual network peering. Virtual network peering allows you to create low-latency, high-bandwidth connections between virtual networks without using gateways or the internet1.

To create a virtual network peering, you need to go to the Azure portal and select your virtual network. Then select Peerings under Settings and select + Add2.

On the Add peering page, enter or select the following information:

Name: Type a unique name for the peering from the source virtual network to the destination virtual network.

Virtual network deployment model: Select Resource manager.

Subscription: Select the subscription that contains the destination virtual network.

Virtual network: Select the destination virtual network from the list or enter its resource ID.

Name of the peering from [destination virtual network] to [source virtual network]: Type a unique name for the peering from the destination virtual network to the source virtual network.

Configure virtual network access settings: Select Enabled to allow resources in both virtual networks to communicate with each other.

Allow forwarded traffic: Select Disabled to prevent traffic that originates from outside either of the peered virtual networks from being forwarded through either of them.

Allow gateway transit: Select Disabled to prevent either of the peered virtual networks from using a gateway in the other virtual network.

Use remote gateways: Select Disabled to prevent either of the peered virtual networks from using a gateway in the other virtual network as a transit point to another network.

Select Add to create the peering2.

Repeat the previous steps to create peerings between VNET2 and VNET1, and between VNET2 and VNET3. This will allow hosts on VNET2 to access hosts on both VNET1 and VNET3.

To prevent hosts on VNET1 and VNET3 from communicating through VNET2, you need to use network security groups (NSGs) to filter traffic between subnets. NSGs are rules that allow or deny inbound or outbound traffic based on source or destination IP address, port, or protocol3.

To create an NSG, you need to go to the Azure portal and select Create a resource. Search for network security group and select Network security group. Then select Create4.

On the Create a network security group page, enter or select the following information:

Subscription: Select your subscription name.

Resource group: Select your resource group name.

Name: Type a unique name for your NSG.

Region: Select the same region as your virtual networks.

Select Review + create and then select Create to create your NSG4.

To add rules to your NSG, you need to go to the Network security groups service in the Azure portal and select your NSG. Then select Inbound security rules or Outbound security rules under Settings and select + Add4.

On the Add inbound security rule page or Add outbound security rule page, enter or select the following information:

Source or Destination: Select CIDR block.

Source CIDR blocks or Destination CIDR blocks: Enter the IP address range of the source or destination subnet that you want to filter. For example, 10.0.1.0/24 for VNET1 subnet 1, 10.0.2.0/24 for VNET2 subnet 1, and 10.0.3.0/24 for VNET3 subnet 1.

Protocol: Select Any to apply the rule to any protocol.

Action: Select Deny to block traffic from or to the source or destination subnet.

Priority: Enter a number between 100 and 4096 that indicates the order of evaluation for this rule. Lower numbers have higher priority than higher numbers.

Name: Type a unique name for your rule.

Select Add to create your rule4.

Repeat the previous steps to create inbound and outbound rules for your NSG that deny traffic between VNET1 and VNET3 subnets. For example, you can create an inbound rule that denies traffic from 10.0.1.0/24 (VNET1 subnet 1) to 10.0.3.0/24 (VNET3 subnet 1), and an outbound rule that denies traffic from 10.0.3.0/24 (VNET3 subnet 1) to 10.0.1.0/24 (VNET1 subnet 1).

To associate your NSG with a subnet, you need to go to the Virtual networks service in the Azure portal and select your virtual network. Then select Subnets under Settings and select the subnet that you want to associate with your NSG5.

On the Edit subnet page, under Network security group, select your NSG from the drop-down list. Then select Save5.

Repeat the previous steps to associate your NSG with the subnets in VNET1 and VNET3 that you want to isolate from each other.

Here are the steps and explanations for ensuring that all hosts deployed to subnet3-2 connect to the internet by using the same static public IP address:

To use the same static public IP address for multiple hosts, you need to create a NAT gateway and associate it with subnet3-2. A NAT gateway is a resource that performs network address translation (NAT) for outbound traffic from a subnet1. It allows you to use a single public IP address for multiple private IP addresses2.

To create a NAT gateway, you need to go to the Azure portal and select Create a resource. Search for NAT gateway, select NAT gateway, then select Create3.

On the Create a NAT gateway page, enter or select the following information and accept the defaults for the remaining settings:

Subscription: Select your subscription name

Resource group: Select your resource group

Name: Type a unique name for your NAT gateway

Region: Select the same region as your virtual network

Public IP address: Select Create new and type a name for your public IP address. Select Standard as the SKU and Static as the assignment method4.

Select Review + create and then select Create to create your NAT gateway3.

To associate the NAT gateway with subnet3-2, you need to go to the Virtual networks service in the Azure portal and select your virtual network.

On the Virtual network page, select Subnets under Settings, and then select subnet3-2 from the list.

On the Edit subnet page, under NAT gateway, select your NAT gateway from the drop-down list. Then select Save.

To provide a single host name that routes traffic based on the origin, you can use Azure Traffic Manager. This service allows you to route traffic to different endpoints based on various routing methods, including geographic routing.

Navigate to the Azure Portal.

Search for “Traffic Manager profiles” and select it.

Click on “Create”.

Enter the following details:

Name: Enter a name for the Traffic Manager profile (e.g., ContosoTrafficManager).

Routing method: Select Geographic.

Subscription: Select your subscription.

Resource group: Select an existing resource group or create a new one.

Resource group location: Choose a location (this does not affect the routing).

Click on “Create”.

Navigate to the newly created Traffic Manager profile.

Select “Endpoints” from the left-hand menu.

Click on “Add” to add a new endpoint.

Enter the following details:

Type: Select External endpoint.

Name: Enter a name for the endpoint (e.g., NewYorkEndpoint).

FQDN: Enter ny.contoso.com.

Geographic region: Select “World” (this will be adjusted later).

Click on “Add” to save the endpoint.

Repeat the process to add the second endpoint:

Type: Select External endpoint.

Name: Enter a name for the endpoint (e.g., GermanyEndpoint).

FQDN: Enter de.contoso.com.

Geographic region: Select Europe.

Navigate to the Traffic Manager profile.

Select “Configuration” from the left-hand menu.

Under “Geographic routing”, adjust the regions:

For the GermanyEndpoint, ensure that the geographic region is set to Europe.

For the NewYorkEndpoint, ensure that the geographic region is set to World (excluding Europe).

Use a DNS query tool to test the routing.

From a location in Germany, query the Traffic Manager profile’s DNS name and ensure it resolves to de.contoso.com.

From a location outside Europe, query the Traffic Manager profile’s DNS name and ensure it resolves to ny.contoso.com.

Azure Traffic Manager: This service uses DNS to direct client requests to the most appropriate endpoint based on the routing method you choose. Geographic routing ensures that traffic is directed based on the origin of the request.

Geographic Routing: This method allows you to route traffic based on the geographic location of the DNS query origin, ensuring that users are directed to the nearest or most appropriate endpoint.

Step-by-Step SolutionStep 1: Create a Traffic Manager ProfileStep 2: Configure EndpointsStep 3: Adjust Geographic RoutingStep 4: Test the ConfigurationExplanationBy following these steps, you can provide a single host name that routes traffic to de.contoso.com for users in Germany and to ny.contoso.com for users from other locations, ensuring efficient and appropriate traffic management.

To create an Azure Firewall instance, you need to go to the Azure portal and select Create a resource. Type firewall in the search box and press Enter. Select Firewall and then select Create1.

To assign an IP address from the address range of 10.1.255.0/24 to the firewall, you need to select a public IP address that belongs to that range. You can either create a new public IP address or use an existing one1.

To use a new Premium firewall policy named FW-policy1, you need to select Premium as the Firewall tier and create a new policy with the name FW-policy12. A Premium firewall policy allows you to configure advanced features such as TLS Inspection, IDPS, URL Filtering, and Web Categories3.

To route traffic directly to the internet, you need to enable SNAT (Source Network Address Translation) for the firewall. SNAT allows the firewall to use its public IP address as the source address for outbound traffic4.

To prevent all Azure hosts outside of subnet1-2 from connecting to TCP port 5585 on hosts within subnet1-2, you can use a Network Security Group (NSG). This solution is straightforward and minimizes administrative effort.

Step-by-Step Solution

Step 1: Create a Network Security Group (NSG)

Navigate to the Azure Portal.

Search for “Network security groups” and select it.

Click on “Create”.

Enter the following details:

Subscription: Select your subscription.

Resource Group: Select an existing resource group or create a new one.

Name: Enter a name for the NSG (e.g., NSG-Subnet1-2).

Region: Select the region where your virtual network is located.

Click on “Review + create” and then “Create”.

Step 2: Create an Inbound Security Rule

Navigate to the newly created NSG.

Select “Inbound security rules” from the left-hand menu.

Click on “Add” to create a new rule.

Enter the following details:

Source: Select Service Tag.

Source Service Tag: Select VirtualNetwork.

Source port ranges: Leave as *.

Destination: Select IP Addresses.

Destination IP addresses/CIDR ranges: Enter the IP range of subnet1-2 (e.g., 10.1.2.0/24).

Destination port ranges: Enter 5585.

Protocol: Select TCP.

Action: Select Deny.

Priority: Enter a priority value (e.g., 100).

Name: Enter a name for the rule (e.g., Deny-TCP-5585).

Click on “Add” to create the rule.

Step 3: Associate the NSG with Subnet1-2

Navigate to the virtual network that contains subnet1-2.

Select “Subnets” from the left-hand menu.

Select subnet1-2 from the list of subnets.

Click on “Network security group”.

Select the NSG you created (NSG-Subnet1-2).

Click on “Save”.

Explanation

Network Security Group (NSG): NSGs are used to filter network traffic to and from Azure resources in an Azure virtual network. They contain security rules that allow or deny inbound and outbound traffic based on source and destination IP addresses, port, and protocol1.

Inbound Security Rule: By creating a rule that denies traffic on TCP port 5585 from any source outside of subnet1-2, you ensure that only hosts within subnet1-2 can connect to this port.

Association with Subnet: Associating the NSG with subnet1-2 ensures that the security rules are applied to all resources within this subnet.

By following these steps, you can effectively prevent all Azure hosts outside of subnet1-2 from connecting to TCP port 5585 on hosts within subnet1-2, while minimizing administrative effort.

To achieve the task of ensuring that virtual machines on VNET1 and VNET2 are included automatically in a DNS zone named contoso.azure, and that they can resolve the names of the virtual machines on either virtual network, you can follow these steps:

Step-by-Step Solution

Step 1: Create a Private DNS Zone

Navigate to the Azure Portal.

Search for “Private DNS zones” in the search bar and select it.

Click on “Create”.

Enter the DNS zone name as contoso.azure.

Select the appropriate subscription and resource group.

Click on “Review + create” and then “Create”.

Step 2: Link VNET1 and VNET2 to the DNS Zone

Go to the newly created DNS zone (contoso.azure).

Select “Virtual network links” from the left-hand menu.

Click on “Add”.

Enter a name for the link (e.g., VNET1-link).

Select the subscription and virtual network (VNET1).

Enable auto-registration to ensure that VMs are automatically registered in the DNS zone.

Click on “OK”.

Repeat the process for VNET2.

Step 3: Configure DNS Settings for VNET1 and VNET2

Navigate to VNET1 in the Azure Portal.

Select “DNS servers” under the “Settings” section.

Ensure that the DNS server is set to “Default (Azure-provided)”.

Repeat the process for VNET2.

Step 4: Verify Name Resolution

Deploy a virtual machine in VNET1 and another in VNET2.

Connect to the virtual machines using Remote Desktop Protocol (RDP) or Secure Shell (SSH).

Test name resolution by pinging the VM in VNET2 from the VM in VNET1 using its hostname (e.g., ping .contoso.azure).

Explanation

Private DNS Zone: This allows you to manage and resolve domain names in a private network without exposing them to the public internet.

Virtual Network Links: Linking VNET1 and VNET2 to the DNS zone ensures that VMs in these networks can register their DNS records automatically.

Auto-registration: This feature automatically registers the DNS records of VMs in the linked virtual networks, simplifying management.

DNS Settings: Using Azure-provided DNS ensures that the VMs can resolve each other’s names without additional configuration.

By following these steps, you ensure that virtual machines on VNET1 and VNET2 are included automatically in the DNS zone contoso.azure and can resolve each other’s names seamlessly.

To ensure that hosts on VNET1 and VNET2 can communicate with minimal latency, you can use Virtual Network Peering. This method connects the two virtual networks directly through the Microsoft backbone network, ensuring low-latency and high-bandwidth communication.

Step-by-Step Solution

Step 1: Set Up Virtual Network Peering

Navigate to the Azure Portal.

Search for “Virtual networks” and select VNET1.

In the left-hand menu, select “Peerings” under the “Settings” section.

Click on “Add” to create a new peering.

Enter the following details:

Name: Enter a name for the peering (e.g., VNET1-to-VNET2).

Peer virtual network: Select VNET2.

Allow virtual network access: Ensure this is enabled.

Allow forwarded traffic: Enable if needed.

Allow gateway transit: Enable if needed.

Click on “Add”.

Step 2: Configure Peering on VNET2

Navigate to VNET2 in the Azure Portal.

In the left-hand menu, select “Peerings” under the “Settings” section.

Click on “Add” to create a new peering.

Enter the following details:

Name: Enter a name for the peering (e.g., VNET2-to-VNET1).

Peer virtual network: Select VNET1.

Allow virtual network access: Ensure this is enabled.

Allow forwarded traffic: Enable if needed.

Allow gateway transit: Enable if needed.

Click on “Add”.

Explanation

Virtual Network Peering: This feature connects two virtual networks in the same or different regions, allowing resources in both networks to communicate with each other as if they were part of the same network. The traffic between peered virtual networks uses the Microsoft backbone infrastructure, ensuring low latency and high bandwidth12.

Allow Virtual Network Access: This setting ensures that the virtual networks can communicate with each other.

Allow Forwarded Traffic: This setting allows traffic forwarded from a network security appliance in the peered virtual network.

Allow Gateway Transit: This setting allows the peered virtual network to use the gateway in the local virtual network.

By following these steps, you can ensure that hosts on VNET1 and VNET2 can communicate with minimal latency, leveraging the high-speed Microsoft backbone network.

Here are the steps and explanations for ensuring that the storage34280945 storage account will only accept connections from hosts on VNET1:

To restrict network access to your storage account, you need to configure the Azure Storage firewall and virtual network settings for your storage account. You can do this in the Azure portal by selecting your storage account and then selecting Networking under Settings1.

On the Networking page, select Firewalls and virtual networks, and then select Selected networks under Allow access from1. This will block all access to your storage account except from the networks or resources that you specify.

Under Virtual networks, select + Add existing virtual network. Then select VNET1 from the list of virtual networks and select the subnet that contains the hosts that you want to allow access to your storage account1. This will enable a service endpoint for Storage in the subnet and configure a virtual network rule for that subnet through the Azure storage firewall2.

Select Add to add the virtual network and subnet to your storage account1.

Select Save to apply your changes1.

Here are the steps and explanations for creating the object that will provide the IP addressing configuration of the on-premises network to the Site-to-Site VPN:

The object that you need to create is called a local network gateway. A local network gateway represents your on-premises network and VPN device in Azure. It contains the public IP address of your VPN device and the address prefixes of your on-premises network that you want to connect to the Azure virtual network1.

To create a local network gateway, you need to go to the Azure portal and select Create a resource. Search for local network gateway, select Local network gateway, then select Create2.

On the Create local network gateway page, enter or select the following information and accept the defaults for the remaining settings:

Name: Type a unique name for your local network gateway.

IP address: Type the public IP address of your VPN device, which is 131.107.50.60 in this case.

Address space: Type the internal address range of your on-premises network, which is 10.10.0.0/16 in this case.

Subscription: Select your subscription name.

Resource group: Select your resource group name.

Location: Select the same region as your virtual network.

Select Review + create and then select Create to create your local network gateway2.

To archive all the metrics of VNET1 to an existing storage account, you can use Azure Monitor’s diagnostic settings. Here’s how you can do it:

Step-by-Step Solution

Step 1: Navigate to VNET1 in the Azure Portal

Open the Azure Portal.

Search for “Virtual networks” and select VNET1 from the list.

Step 2: Configure Diagnostic Settings

In the VNET1 blade, select “Diagnostic settings” under the “Monitoring” section.

Click on “Add diagnostic setting”.

Step 3: Set Up the Diagnostic Setting

Enter a name for the diagnostic setting (e.g., VNET1-Metrics-Archive).

Select the metrics you want to archive. You can choose from various metrics like TotalBytesReceived, TotalBytesSent, etc.

Under “Destination details”, select “Archive to a storage account”.

Choose the existing storage account where you want to archive the metrics.

Configure the retention period if needed.

Step 4: Save the Configuration

Review your settings to ensure everything is correct.

Click on “Save” to apply the diagnostic setting.

Explanation

Diagnostic Settings: These allow you to collect and route metrics and logs from your Azure resources to various destinations, including storage accounts, Log Analytics workspaces, and Event Hubs.

Metrics: Metrics provide numerical data about the performance and health of your resources. Archiving these metrics helps in long-term analysis and compliance.

Storage Account: Using an existing storage account ensures that the metrics are stored securely and can be accessed for future analysis.

By following these steps, you can ensure that all the metrics of VNET1 are archived to your existing storage account, enabling you to monitor and analyze the performance and health of your virtual network over time.

No

subnet1(WM1->NSG1 outbound->NSG10 outbound)->subnet2(NSG1 inbound->NSG11 inbound->VM2)

Yes

NSG10 blocks ICMP from VNet4 (source 10.10.0.0/16) but it is not blocked from VM2ג€™s subnet (VNet1/Subnet2).

No

NSG11 blocks RDP (port TCP 3389) destined for ג€˜VirtualNetworkג€™. VirtualNetwork is a service tag and means the address space of the virtual network (VNet1) which in this case is 10.1.0.0/16. Therefore, RDP traffic from subnet2 to anywhere else in VNet1 is blocked.

Box 1: VM2, VM3 and VM4.

VM1 is in VNet1/Subnet1. VNet1 is peered with VNet2 and VNet3.

There are no NSGs blocking outbound ICMP from VNet1. There are no NSGs blocking inbound ICMP to VNet1/Subnet2, VNet2 or VNet3. Therefore, VM1 can ping VM2 in VNet1/Subnet2, VM3 in VNet2 and VM4 in VNet3.

Box 2:

VM4 is in VNet3. VNet3 is peered with VNet1 and VNet2. There are no NSGs blocking outbound ICMP from VNet3. There are no NSGs blocking inbound ICMP to VNet1/Subnet1, VNet1/Subnet2 or VNet2 from VNet3 (NSG10 blocks inbound ICMP from VNet4 but not from VNet3). Therefore, VM4 can ping VM1 in VNet1/Subnet1, VM2 in VNet1/Subnet2 and VM3 in VNet2.

Box 2: One NSG

The minimum requirement is one NSG. You could attach the NSG to VMScaleSet1 and restrict outbound traffic, or you could attach the NSG to VMScaleSet2 and restrict inbound traffic. Either way you would need two custom NSG rules.

Box 1: Two custom rules

With the NSG attached to VMScaleSet2, you would need to create a custom rule blocking all traffic from VMScaleSet1. Then you would need to create another custom rule with a higher priority than the first rule that allows traffic on port 443.

The default rules in the NSG will allow all other traffic to VMScaleSet2.

For the first question, only ExpressRoute GW SKU Ultra Performance support FastPath feature.

For the second question, vnet1 will connect to ExpressRoute gw, once Vnet1 peers with Vnet2, the traffic from on-premise network will bypass GW and Vnet1, directly goes to Vnet2, while this feature is under public preview.

====Reference

ExpressRoute virtual network gateway is designed to exchange network routes and route network traffic. FastPath is designed to improve the data path performance between your on-premises network and your virtual network. When enabled, FastPath sends network traffic directly to virtual machines in the virtual network, bypassing the gateway.

To configure FastPath, the virtual network gateway must be either:

Ultra Performance

ErGw3AZ

VNet Peering - FastPath will send traffic directly to any VM deployed in a virtual network peered to the one connected to ExpressRoute, bypassing the ExpressRoute virtual network gateway.

https://docs.microsoft.com/en-us/azure/expressroute/about-fastpath

Gateway SKU

https://docs.microsoft.com/en-us/azure/expressroute/expressroute-about-virtual-network-gateways

VNet 1 will get the default from BGP and propagate it to VNET 2 and 3

To minimize the risk of SNAT port exhaustion for your 100 virtual machines in subnet4-1, while ensuring minimal administrative effort, you can use an Azure NAT Gateway. This service provides scalable and resilient outbound connectivity for virtual networks, dynamically allocating SNAT ports to avoid exhaustion.

Navigate to the Azure Portal.

Search for “NAT gateways” and select it.

Click on “Create”.

Enter the following details:

Subscription: Select your subscription.

Resource Group: Select an existing resource group or create a new one.

Name: Enter a name for the NAT gateway (e.g., NATGateway-Subnet4-1).

Region: Select the region where your virtual network is located.

Click on “Next: Outbound IP”.

Choose whether to use existing public IP addresses or create new ones.

If creating new ones, click on “Add new” and configure the new public IP addresses.

Click on “Next: Subnet”.

Click on “Associate subnet”.

Select the virtual network that contains subnet4-1.

Select subnet4-1 from the list of subnets.

Click on “OK”.

Review your settings to ensure everything is correct.

Click on “Review + create” and then “Create”.

Azure NAT Gateway: This service provides outbound connectivity for virtual networks, dynamically allocating SNAT ports across all VM instances within a subnet. This dynamic allocation helps prevent SNAT port exhaustion, especially in scenarios with high outbound connection volumes12.

Dynamic SNAT Port Allocation: Unlike static allocation methods, NAT Gateway dynamically allocates SNAT ports based on demand, ensuring efficient use of available ports and reducing the risk of exhaustion2.

Step-by-Step SolutionStep 1: Create a NAT GatewayStep 2: Configure Outbound IP AddressesStep 3: Associate the NAT Gateway with Subnet4-1Step 4: Review and CreateExplanationBy following these steps, you can ensure that your 100 virtual machines in subnet4-1 can make the necessary API calls without running into SNAT port exhaustion, all while minimizing administrative effort.