Cloud computing has always promised agility, productivity, and unlimited scale, but rarely do the default settings underpinning these promises curtail security in as direct a way as Microsoft's implementation of default outbound access for Azure virtual machines. As Azure races toward retiring this default behavior in September, the industry faces a subtle but seismic shift—one with wide-ranging consequences for developers, security teams, and anyone whose workflow has ever quietly relied on that “magic” internet access.
When Microsoft launched Azure, it sought to lower the barrier for deployment—particularly for developers less versed in the intricacies of networking. By default, any new VM deployed within an Azure Virtual Network (VNet) could initiate outbound internet connections without additional configuration. The simplicity concealed a risk: without explicit control, outbound traffic from these VMs could escape security controls, audit trails, or even basic awareness by the central IT or security teams.
Chris McHenry, Chief Product Officer at Aviatrix—a specialist in secure multi-cloud networking—frames it starkly: “Developers don’t typically understand networking... So if you deploy an app, by default, it has internet access. You don’t have to do anything. You don’t really have the ability to control it.” This frictionless experience now hits a brick wall: after September, new or altered VMs in Azure will no longer be granted default outbound connectivity. To access the internet, explicit networking setup will be mandatory.
McHenry explains the operational dilemma: “The security team no longer has any visibility, and they no longer have any control. In Microsoft, the lack of any configuration indicates that you have internet access. You’re going back and reversing a lot of configuration.” This lack of transparency runs counter to modern security best practices, especially as organizations embrace Zero Trust principles and must prove not only that their networks are segmented and monitored, but that all data egress is justified and logged.
McHenry identifies three common industry reactions:
This historic Azure difference means many workloads, deployments scripts, and build pipelines have developed a casual reliance on “out of the box” connectivity—sometimes without operational teams realizing it. Correcting for this will require effort, testing, and, in many cases, new network resources.
Security postures, meanwhile, are at risk of regression. Assigning static public IPs, if not shielded by firewalls or at least rigorous network security group (NSG) rules, increases external exposure and may violate organizational or regulatory requirements. Worse, rushed fixes undertaken close to the deadline could inadvertently weaken controls.
There’s also the risk of operational complexity. Where previously developers could spin up new workloads without engaging with networking teams, networking must now be front-loaded into the development process. This requires improved cross-team collaboration and may slow development velocity until new best practices are established.
Finally, there is a financial dimension. None of Microsoft’s recommended solutions are free. NAT gateways, additional public IPs, firewalls, and even some advanced load balancing configurations incur ongoing charges. For organizations with hundreds or thousands of VMs, these costs will compound, and budgets will need adjustment.
Forward-thinking enterprises should seize this as a trigger for broader networking hygiene:
Microsoft’s initial reticence to promote Azure Firewall as the default fix highlights the cost/operational tension inherent in these changes. Azure Firewall, though costly, remains the gold standard, not merely restoring technical function but enhancing security posture. Enterprises should resist the impulse to simply “get things working” and instead embrace the opportunity to architect for visibility, compliance, and future scalability.
Security researchers and industry analysts point to similar transitions at AWS and Google. While both platforms required explicit outbound configuration from inception, both have faced incidents and outages where unmonitored egress was implicated in data loss or system compromise. The Azure shift, therefore, brings it into alignment with community expectations—if several years behind the curve.
There remains, however, a significant burden on Microsoft to provide clear, actionable guidance. McHenry’s comments about customer negotiations and industry skepticism show that communication—or its lack—can be as damaging as the technical change itself.
This transition will be painful for organizations slow to adapt, but it is an unavoidable and, ultimately, positive step forward. Enterprises should leverage this moment to modernize—not merely patch—their cloud presence: automating security, enforcing observability, and building resilience for whatever the next wave of cloud transformation might bring.
As September approaches, the best-prepared organizations will be those who see beyond the immediate fix to a broader vision—where every outbound packet is both visible and controlled, and where “default” means “secure,” not “permissive.” The coming months will be busy for many Azure admins, but with thoughtful planning, they need not be anxious ones.
Source: theregister.com Microsoft to retire default outbound access for VMs in Azure
The End of an Era: What’s Changing for Azure VMs
When Microsoft launched Azure, it sought to lower the barrier for deployment—particularly for developers less versed in the intricacies of networking. By default, any new VM deployed within an Azure Virtual Network (VNet) could initiate outbound internet connections without additional configuration. The simplicity concealed a risk: without explicit control, outbound traffic from these VMs could escape security controls, audit trails, or even basic awareness by the central IT or security teams.Chris McHenry, Chief Product Officer at Aviatrix—a specialist in secure multi-cloud networking—frames it starkly: “Developers don’t typically understand networking... So if you deploy an app, by default, it has internet access. You don’t have to do anything. You don’t really have the ability to control it.” This frictionless experience now hits a brick wall: after September, new or altered VMs in Azure will no longer be granted default outbound connectivity. To access the internet, explicit networking setup will be mandatory.
Why Retire Default Outbound Access?
The move is less about product evolution and more a response to security realities. On-premises deployments traditionally offered security teams clear visibility and control over where data flowed. With Azure’s default setup, that visibility vanished. The central issue: with a default “allow all outbound” model, organizations could lose track of what was connecting where, and crucially, from which IP addresses.McHenry explains the operational dilemma: “The security team no longer has any visibility, and they no longer have any control. In Microsoft, the lack of any configuration indicates that you have internet access. You’re going back and reversing a lot of configuration.” This lack of transparency runs counter to modern security best practices, especially as organizations embrace Zero Trust principles and must prove not only that their networks are segmented and monitored, but that all data egress is justified and logged.
Who Will Be Affected (And Who Won't)?
Microsoft’s change only applies to new deployments or modifications of existing ones after the deadline. Legacy resources, if left untouched, will continue to work as before—at least until they are updated or redeployed. This creates a bifurcated environment during the transition period: existing pipelines may continue smoothly, but any attempt to scale horizontally, create new VM instances, or otherwise modify infrastructure could result in failure unless outbound connectivity is purposefully configured.McHenry identifies three common industry reactions:
- Total Surprise: Many organizations are unaware of the looming change. Their pipelines and automation may quietly rely on default outbound access, and the risk is only now surfacing.
- Skepticism: Some believe the date may slip, as has occasionally happened before, and plan to “risk it,” betting on delays or grace periods from Microsoft.
- Active Negotiation: Large or highly exposed enterprises are in discussions with Microsoft seeking deferrals, extensions, or guidance.
How Does Azure Compare to AWS and GCP?
One reason for the alarm surrounding Azure's change is that its peers—AWS and Google Cloud Platform—require explicit setup for outbound connectivity. In AWS, for instance, a VM (EC2 instance) has no outbound internet access unless it routes traffic through an Internet Gateway by way of routing table configuration. GCP adopts a similarly explicit model.This historic Azure difference means many workloads, deployments scripts, and build pipelines have developed a casual reliance on “out of the box” connectivity—sometimes without operational teams realizing it. Correcting for this will require effort, testing, and, in many cases, new network resources.
The New Connectivity Options: What Will Replace Default Access?
Microsoft’s recommendations for those affected fall into several technical buckets:- Assigning Fixed Public IP Addresses: By pinning a public IP to each VM, outbound access is restored in an explicit, auditable way. However, as McHenry notes, “there was a literal groan from the audience, because it actually moves your security posture backwards.” It increases attack surface and can complicate compliance.
- NAT Gateways: Azure’s NAT Gateway allows VNets to route outbound traffic through a fixed public IP, centralizing egress while reducing management overhead. The solution maintains some security posture but does not natively add visibility or controls over the actual content of outgoing traffic. And, like all premium Azure services, it carries extra cost—potentially significant for large-scale environments.
- Azure Load Balancers and Firewalls: These offer further granularity. Users could leverage outbound rules via Azure Load Balancers or implement Azure Firewall in their outbound flow. However, as McHenry astutely observes, Microsoft surprisingly stops short of highlighting Azure Firewall as the go-to solution, possibly because of associated cost. Firewalls deliver the visibility and policy controls now required for Zero Trust, but may stretch budgets, especially at enterprise scale.
What Are the Big Risks?
The most immediate risk is technical disruption. Automated deployment pipelines, continuous integration/continuous deployment (CI/CD) flows, and auto-scaling operations that assume default outbound connectivity may break after the cutover. Organizations that do not track every pipeline’s reliance on outbound access could experience failed deployments—sometimes at critical moments.Security postures, meanwhile, are at risk of regression. Assigning static public IPs, if not shielded by firewalls or at least rigorous network security group (NSG) rules, increases external exposure and may violate organizational or regulatory requirements. Worse, rushed fixes undertaken close to the deadline could inadvertently weaken controls.
There’s also the risk of operational complexity. Where previously developers could spin up new workloads without engaging with networking teams, networking must now be front-loaded into the development process. This requires improved cross-team collaboration and may slow development velocity until new best practices are established.
Finally, there is a financial dimension. None of Microsoft’s recommended solutions are free. NAT gateways, additional public IPs, firewalls, and even some advanced load balancing configurations incur ongoing charges. For organizations with hundreds or thousands of VMs, these costs will compound, and budgets will need adjustment.
The Security Upside—and the Organizational Reckoning
Despite the pain of transition, industry experts widely endorse Microsoft’s decision. Retiring default outbound access aligns Azure with the security-first postures of its competitors and addresses decades-long criticisms from the enterprise security community. McHenry points to the long-term advantages: “This change... is an opportunity for organizations to reassess what their security posture looks like.” Rather than perpetuate unmonitored and uncontrolled egress, organizations can now enforce and audit every data flow.Forward-thinking enterprises should seize this as a trigger for broader networking hygiene:
- Review all deployment scripts and pipelines. Identify assumptions about internet access, and refactor as necessary.
- Inventory workloads that require outbound connectivity. Migrate them to use NAT gateways or firewalls, not public IP assignments, wherever practical.
- Formalize network egress policies, ensuring all traffic passes through monitored, controlled, and logged interfaces.
- Provide training to developers and DevOps staff, closing the knowledge gap on basic cloud networking and security.
- Update documentation for onboarding and deployment processes to reflect the new reality, preventing “tribal knowledge” failures when staff or contractors change.
A Temporary Patch or a Permanent Shift?
There remains a temptation to treat this as a one-time adjustment, but cloud computing’s history is littered with the remnants of “temporary measures” that persist for years. Default egress was always a hidden liability, and while its retirement feels sudden, the trend across all major providers is toward explicit, controlled, and observable networking.Microsoft’s initial reticence to promote Azure Firewall as the default fix highlights the cost/operational tension inherent in these changes. Azure Firewall, though costly, remains the gold standard, not merely restoring technical function but enhancing security posture. Enterprises should resist the impulse to simply “get things working” and instead embrace the opportunity to architect for visibility, compliance, and future scalability.
What Should Enterprises Do Now?
With the September cutoff fast approaching, IT and security leaders must act with urgency but also with care:- Audit all Azure VMs, classifying them by need for outbound access and exposure. Use Azure’s diagnostic tools to analyze current behavior.
- Engage application owners and developers in cross-functional teams. Ensure everyone understands where defaults will break and how to remediate at both technical and process levels.
- Pilot changes in dev/test environments before broad rollout. Watch for edge cases—third-party dependencies, update scripts, OS activation routines—that might quietly rely on outbound connectivity.
- Budget for new costs as part of ongoing cloud spend forecasts.
Community Impact and Broader Industry Context
For some in IT, this change evokes shades of the Y2K changeover: unlikely to cause apocalypse, but certain to reveal deeply buried and long-ignored dependencies. The fact that so many organizations are only now becoming aware of the risk underlines a persistent challenge in cloud: the gulf between what is possible and what is secure by default.Security researchers and industry analysts point to similar transitions at AWS and Google. While both platforms required explicit outbound configuration from inception, both have faced incidents and outages where unmonitored egress was implicated in data loss or system compromise. The Azure shift, therefore, brings it into alignment with community expectations—if several years behind the curve.
There remains, however, a significant burden on Microsoft to provide clear, actionable guidance. McHenry’s comments about customer negotiations and industry skepticism show that communication—or its lack—can be as damaging as the technical change itself.
Looking Forward: Cloud Security Matures
Ultimately, Azure’s retirement of default outbound access should be seen not as an obstacle but as an inflection point in the maturity of cloud networking. The days when “just get it running” trumped careful security are receding; the new era is one where operational agility and robust, explicit controls must coexist.This transition will be painful for organizations slow to adapt, but it is an unavoidable and, ultimately, positive step forward. Enterprises should leverage this moment to modernize—not merely patch—their cloud presence: automating security, enforcing observability, and building resilience for whatever the next wave of cloud transformation might bring.
As September approaches, the best-prepared organizations will be those who see beyond the immediate fix to a broader vision—where every outbound packet is both visible and controlled, and where “default” means “secure,” not “permissive.” The coming months will be busy for many Azure admins, but with thoughtful planning, they need not be anxious ones.
Source: theregister.com Microsoft to retire default outbound access for VMs in Azure
