The Azure Outbound Access Deadline You Can’t Ignore

March 31, 2025 in cloud security, Azure, cloud firewall By Bryan Ashley

At the Microsoft Ignite conference in November 2024, I discovered something very worrying: many Azure customers have no idea about the major changes coming to Azure outbound access in September 2025 that could break their cloud connectivity overnight. Starting September 30, 2025, new Azure Virtual Machines (VMs) will no longer have default outbound internet access.

This means:

• No automatic internet access for new Azure VMs
• No silent “lifeline” for cloud services that rely on outbound connectivity
• No more quick and easy test workloads which require Internet access

With only months to prepare, network admins and architects need to know unless you explicitly configure outbound access, your workload could stop working. This network change could cause downtime, deployment delays, and operational headaches.

What’s Changing and Why?

Azure is transitioning from a model where virtual machines (VMs) in a virtual network are automatically assigned a default outbound public IP address to a more secure approach requiring explicit outbound internet access configuration.

Thats a pretty tech heavy explanation, so let’s break this down. Today, anyone who spins up a workload in an Azure VNet automatically has Internet access – nothing else needs to be deployed, Internet access is just available as soon as the workload is ready to go.

Microsoft recognized this may not be something that security professionals love since they are tasked with ensuring workloads are protected from Internet risks and need to know when new things are talking to the Internet. The new change is meant to address that risk. After September 30, 2025, you will be able to spin up the workload all day long, but you won’t get Internet access until you take some additional steps.

Think of it like this:

• Before: Every house (VM) in your gated community (Azure network) automatically gets a key to exit through the main gate (internet).
• After: New houses won’t get keys by default. If you need access, you must explicitly request a key and manage access yourself.

So… this seems like a good thing?

This change will improve security, but it also creates some major challenges for cloud architects, security teams, and developers.

• If you are a security professional, this may be music to your ears, but how do you view, manage, a control policy across these new networking services for internet access?
• If you are a developer, what updates do you need to make to your automation templates to account for this change and will you now have to wait on security to approve firewall changes?
• If you are a cloud architect, how do you make sure that you keep architectural consistency across these various options and what are the implications for each?

Here’s how this change will affect your Azure infrastructure and what you can do about it:

How the Change to Outbound Access will Affect Your Deployments

The retirement of default outbound internet access will primarily impact new Azure deployments after September 2025. Existing deployments will not be affected immediately, but customers need to plan for the change. The implications vary based on the type of workload and application architecture.

• For Infrastructure as a Service (IaaS) deployment, such as virtual machines (VMs) without public IP addresses, explicit outbound access configuration will be required. This requirement could mean using Azure’s native solutions like NAT gateways or load balancers, or third-party networking solutions like Aviatrix’s Secure Cloud Networking Platform.
• Platform as a Service (PaaS) and Software as a Service (SaaS) offering may be less impacted, as Microsoft is expected to handle the necessary configurations for managed services. However, customers should still review their architectures and dependencies to identify potential issues.
• Application architectures with internet-facing components, like web servers or APIs, may require additional considerations for outbound connectivity, such as securing egress traffic or managing network security group (NSG) rules. Architectures relying on hybrid or multicloud connectivity may also need to adjust their network configurations.

By removing default outbound internet access, Microsoft is shifting to a more controlled, secure-by-default model. Now, administrators must intentionally define outbound policies, ensuring only approved traffic reaches external destinations. This provides better governance, stricter policy enforcement, and reduced attack surfaces, aligning with Zero Trust security principles.

New challenges for your security

While this change improves security, it also introduces operational complexity. Many applications, automation scripts, and third-party services currently rely on implicit outbound access, and without proactive planning, these workloads could break. Large-scale environments with thousands of VMs will require careful inventory assessment, manual configuration, and ongoing policy management, which can become an administrative burden.

How to Ensure Your Azure Network Doesn’t Break

If you’re relying on default outbound internet access in Azure today, you need to put a plan in place. Without proactive planning, your applications may fail, security policies could be bypassed, and troubleshooting will become significantly harder.

The good news? You have multiple options to regain control over outbound connectivity—but not all solutions are equal. You can choose between native Azure options and third-party solutions.

Option #1: Native Azure Options for Secure Outbound Access

Here are the native Azure options you can use to create secure outbound access:

1. Public IP Addresses — Assigning public IP addresses to individual VMs or VM scale sets allows direct outbound internet access. However, this approach can be costly and difficult to manage at scale.
2. Load Balancer — An Azure Load Balancer with public IP can provide outbound internet access for backend pool members. This is a more centralized approach but may require additional configuration.
3. NAT Gateway — A managed service that provides outbound internet connectivity for virtual networks. It offers a simple and cost-effective solution, but with limited customization options.

Option #2: Third-Party Solutions for Secure Outbound Access

If you’re looking for other options to set up secure outbound access for new Azure VMs, you can turn to third-party solutions like ours that offer advanced networking and security solutions for multicloud environments.

Third-party solutions like Aviatrix can augment native offerings to provide advanced security controls for enterprise customers looking for more. Through our Cloud Firewall solution, Aviatrix provides a fully integrated, scalable, and secure approach to outbound connectivity—without compromising performance or manageability:

• A consistent egress security framework across all major cloud service providers (CSPs)
• Centralized policy enforcement
• A distributed security model that supports policy as code, integrating security into developers’ CI/CD pipelines without friction
• Granular security controls
• Compliance support
• Deep and holistic observability across all cloud environments

This approach bridges the gap between security, networking, and DevOps, allowing enterprises to maintain cloud speed and agility while enforcing robust security and operational control at scale.

The choice between native Azure options and third-party solutions depends on factors like complexity, scale, security requirements, and operational needs. Native options may suit simpler deployments, while third-party solutions offer more advanced capabilities for complex, multicloud environments.

Action Plan: What You Need to Do Today to Ensure Secure Outbound Access

We still have a few months before default outbound access for new Azure VMs ends. Starting now, you should assess your current Azure environment and identify resources that may require outbound internet access.

To ensure a smooth transition, I suggest taking the following steps:

• Inventory Assessment — Conduct a comprehensive inventory of your Azure resources, including VMs, web apps, functions, and other services that require outbound internet access.
  • Note: This step can be one of the biggest challenges for administrators in identifying where in their environments they are currently leveraging default outbound access. Aviatrix can help here by automatically inventorying your cloud footprint to highlight these areas of impact.
• Impact Analysis — Evaluate the potential impact of the policy change on your existing deployments and identify resources that may be affected.
• Outbound Access Configuration — Explore the available options for enabling explicit outbound internet access, such as public IP addresses, load balancers, or Azure NAT gateways. Choose the appropriate solution based on your requirements and architecture.
• Testing and Validation — Test your configurations in a non-production environment to ensure seamless operation and compatibility with your applications and services.
• Documentation and Knowledge Transfer — Document the changes made and ensure that relevant team members are aware of the new configurations and processes.
• Monitoring and Maintenance — Implement monitoring and maintenance processes to ensure ongoing compliance with the new policy and address any issues that may arise.

Don’t let the Azure changes blindside your company – use every spare moment of the next few months to develop a plan for secure, high-performance outbound access for your Azure VMs. Proactively prepare for the upcoming change and maintain a secure and compliant Azure environment.

• Listen to my conversation on the change to Azure outbound access with Daniel Mauser, Principal Solution Specialist and Azure Global Black Belt at Microsoft.
• Explore how Aviatrix can prepare you for September 2025.