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.