Microsoft has announced a significant change to Azure Virtual Machine security: the deprecation of Default Outbound Internet Access. This feature, which has been a default behavior for many years, allowed virtual machines to connect to internet resources without explicit configuration. However, this implicit connectivity has been identified as a potential security risk.
Why the Change?
Default Outbound Internet Access can inadvertently expose virtual machines to potential threats. By removing this feature, Microsoft aims to enhance the security posture of Azure environments. This move encourages customers to adopt more secure and controlled outbound connectivity methods.
What Does This Mean for You?
Starting September 30, 2025, virtual machines will require explicit outbound connectivity configurations. Customers will need to choose from the following options:
- Attach a Dedicated Public IP Address: Assign a unique public IP address to the virtual machine, enabling direct internet access. This approach is suitable for scenarios where the VM requires direct public connectivity.
- Deploy a NAT Gateway: Create a NAT gateway and associate it with the virtual machine's subnet. The NAT gateway will translate private IP addresses to public IP addresses, allowing outbound traffic to flow to the internet.
- Use Load Balancer Outbound Rules: Configure outbound rules on a load balancer to route traffic from virtual machines to the internet. This option is useful for scenarios where you need to control and monitor outbound traffic.
- Deploy a Network Virtual Appliance (NVA): Utilize a network virtual appliance like Azure Firewall to perform SNAT and filter outbound traffic. This approach provides advanced security features and granular control over internet access.
Preparing for the Change
To ensure a smooth transition, Azure customers should:
- Assess Current Workloads: Identify virtual machines that require internet access and plan the appropriate connectivity method.
- Implement Security Best Practices: Adopt strong security measures, such as network segmentation, access controls, and regular security assessments.
- Test and Validate: Thoroughly test the new outbound connectivity configurations to avoid disruptions.
- Stay Updated: Monitor Microsoft's documentation and announcements for the latest information and guidance.
By proactively addressing this change, organizations can maintain the security and reliability of their Azure deployments.
Whether you are looking to understand the risks and challenges better or need help implementing the changes, Helient is here to support you. Reach out to us anytime to discuss how we can help you ensure your Azure environment continues to communicate as you intended.