Network Segmentation vs. VLAN: Which Strategy Delivers True Security?

Ensuring network resilience has never been more important. As organizations expand their digital ecosystems to include on-premises systems, cloud platforms, and remote environments, the complexity of securing data and resources grows exponentially. Cyber threats are no longer limited to breaching the network perimeter; attackers now exploit vulnerabilities within internal networks, moving laterally to gain access to critical assets. This heightened risk has driven businesses to adopt network segmentation strategies – ranging from traditional methods like VLANs to more modern, granular approaches – to strengthen their defenses and block lateral movement. 

VLANs have long been a cornerstone of segmentation practices, with 30% of cyber professionals reporting they use VLANs to segment their networks today, but they often fall short of meeting modern, dynamic networks’ demands. On the other hand, more advanced network segmentation provides a dynamic, flexible, and robust solution, offering the granularity needed to implement a Zero Trust architecture.  

Today we will detail the key differences between VLANs and modern network segmentation, delving into their unique benefits, limitations, and use cases. By understanding these distinctions, organizations can make informed decisions on how to best protect their network infrastructure against evolving threats.  

Why Is Network Segmentation (of Any Kind) Important?  

Network segmentation is a foundational practice in modern cybersecurity because it directly addresses the growing complexity and scale of today’s networks. As organizations increasingly adopt hybrid infrastructures – combining on-premises systems, multi-cloud platforms, and remote access solutions – the attack surface has expanded, creating new vulnerabilities. Meanwhile, businesses are struggling to secure these ever-expanding networks with 64% of IT and security leaders connecting over 5,000 assets to their corporate networks.  

According to a report by IBM, the average cost of a data breach reached $4.88 million in 2024, with lateral movement being a contributing factor in nearly 25% of breaches. By implementing segmentation strategies, organizations can reduce their attack surface, limit lateral movement, and contain potential breaches before they escalate.   

Beyond threat containment, network segmentation also plays a vital role in regulatory compliance. Frameworks like PCI DSS, NYDFS, HIPAA, and GDPR mandate strict controls over sensitive data, and segmentation helps organizations meet these requirements by isolating systems that store and process regulated information. This isolation simplifies audits and enhances visibility, allowing security teams to pinpoint vulnerabilities and address them more effectively. Network segmentation strategies also align with the Zero Trust model, which emphasizes verifying every user and device before granting access, further reducing the likelihood of unauthorized activity.  

VLANs: Enhancing Security, but Falling Behind  

VLANs (Virtual Local Area Networks) have been a foundational tool in network segmentation, offering a straightforward and cost-effective way to logically separate networks without requiring additional physical infrastructure. They allow organizations to isolate devices and traffic based on departments, functions, or locations and are widely used in environments where physical segmentation isn’t feasible. However, as Crystal Chadwick, a Customer Engineer at Zero Networks, points out, “A VLAN is a very simple but ineffective way to separate networks.” This simplicity often leads to significant security gaps in modern, dynamic environments.  

VLAN Fundamentals  

VLANs operate by tagging traffic and assigning it to specific virtual networks, creating logical boundaries within a single physical network. This allows for flexibility in grouping devices and managing traffic flows.  

Common Uses of VLANs: VLANs are often used to isolate traffic for specific departments (e.g., finance or HR), segment VoIP systems, or create separate guest networks.  

How VLANs Work: They function at Layer 2 of the OSI model, enabling devices within the same VLAN to communicate directly while restricting communication with other VLANs unless explicitly permitted.  

Basic Benefits: The benefits of a VLAN include separation of networks which then allows them to be segmented by firewalls between gateways, reduction of scope for auditing, and improved identification of assets by network addresses. While these benefits make VLANs attractive for basic network segmentation, their limitations are becoming increasingly apparent in today’s complex threat landscape.  

Using VLANs to Block Lateral Movement  

VLANs can help reduce lateral movement by isolating traffic between different segments. For example, a VLAN might separate a production environment from a development environment, reducing the risk of vulnerabilities in one impacting the other. However, as Chadwick explains, “VLANs are falling behind in effectiveness because they are often full of holes so that no traffic between them is impeded. They give a false sense of security by appearing to segment assets when, in reality, they aren't properly configured for segmentation.”  

Poorly managed VLANs often accumulate allow-rules over time, creating a “Swiss cheese” effect where gaps in the configuration allow unauthorized traffic to flow freely. This lack of proper segmentation makes VLANs vulnerable to attacks such as VLAN hopping, where malicious actors exploit misconfigurations to bypass restrictions. While VLANs might create the illusion of security, their effectiveness hinges on meticulous configuration and maintenance, which many organizations struggle to achieve at scale.  

By implementing VLANs in conjunction with more robust tools like firewalls, Zero Trust policies, and microsegmentation, organizations can address these gaps. Chadwick emphasizes that VLANs should not be the endpoint of a segmentation strategy but a foundational tool that works as part of a layered, resilient approach to network security.  

Five Disadvantages of VLANs  

While VLANs offer a cost-effective and straightforward method for segmenting networks, they fall short in addressing the complexities and advanced threats of modern cybersecurity. Below are some of the key disadvantages of relying on VLANs as the primary segmentation strategy:  

1. Misconfigurations Lead to Vulnerabilities  

VLANs are only as effective as their configurations, and improper setups can introduce significant vulnerabilities. As Chadwick highlights, “VLANs often end up looking like Swiss cheese as allow-rules accumulate, so they don’t really increase protection on either side.” These misconfigurations, such as excessive allow-rules or poorly managed inter-VLAN traffic, create opportunities for attackers to bypass restrictions and move laterally within a network.  

2. False Sense of Security  

One of the biggest pitfalls of VLANs is the illusion of security they create. While they visually segment networks, their actual ability to isolate traffic depends on stringent rule enforcement. Chadwick emphasizes, “VLANs give a false sense of security by appearing to segment assets when in reality they aren't properly configured for segmentation.” This false confidence can leave organizations exposed, believing they are protected when, in fact, their defenses are full of gaps.  

3. Inadequate Against Advanced Threats  

Modern cyber threats such as ransomware and advanced persistent threats (APTs) require segmentation strategies capable of preventing lateral movement and isolating compromised systems. VLANs, operating primarily at Layer 2, lack the granularity and adaptive capabilities needed to counter these sophisticated attacks. Without advanced features like microsegmentation or Zero Trust policies, VLANs alone cannot sufficiently mitigate the risks.  

4. Complexity in Maintenance and Scalability  

Maintaining and scaling VLAN configurations can become a daunting task, especially in dynamic environments like hybrid clouds or multi-site networks. The manual effort required to update VLAN rules across large infrastructures increases the risk of human error and makes VLANs less practical as organizations grow.  

5. Limited Granularity  

VLANs operate at a broad level, dividing networks into larger segments. This approach lacks the fine-grained control provided by more advanced segmentation methods like microsegmentation, where security policies can be enforced at the workload or application level.  

Moving Beyond VLANs  

While VLANs remain a foundational tool for network segmentation, their limitations underscore the need for more comprehensive solutions. Pairing VLANs with technologies like firewalls, Zero Trust Network Access (ZTNA), and automated microsegmentation can fill the gaps and create a layered defense strategy. As Chadwick notes, “VLANs can be a stepping stone, but they need to be complemented by other tools to truly secure a network.”  

How Network Segmentation Strengthens Zero Trust Security Strategies  

As cyberattacks grow more sophisticated, Zero Trust has become a cornerstone of a secure and resilient IT infrastructure. Nine out of ten IT and security pros say Zero Trust is “very” or “extremely” important for improving overall security posture; by isolating systems and restricting access between different areas of the network, segmentation serves as a critical foundation for implementing ZTNA, where no entity is trusted by default and every access request is carefully validated.  

Achieving Zero Trust with Advanced Network Segmentation Methods 

At its core, Zero Trust demands that organizations assume every device, user, and connection could be a potential risk. Network segmentation aligns perfectly with this principle by dividing the network into tightly controlled zones, preventing unrestricted access. 

However, traditional segmentation methods often come with a steep learning curve, significant resource requirements, and technical limitations due to their reliance on outdated tools like VLANs, which are prone to misconfigurations. As a result, many organizations have struggled to implement the key tenets of Zero Trust at scale. By embracing more advanced network segmentation approaches, like modern microsegmentation, organizations move beyond these limitations.  

Modern microsegmentation solutions can automatically learn traffic patterns, identify dependencies, and create highly accurate rules without the need for manual adjustments. This approach ensures segmentation is not only robust enough to accelerate Zero Trust initiatives, but also capable of evolving with the organization’s changing environment — and the changing threat landscape.  

Future-Proofing Network Segmentation with Zero 

As organizations scale, maintaining effective segmentation can prove a challenge. Hybrid environments, multi-cloud infrastructures, and remote workforces all add layers of complexity. Zero Networks addresses these challenges by delivering a solution that adapts to dynamic environments, ensuring consistent protection without compromising performance through an automated, three-step approach:

• Comprehensive Discovery: Zero deploys in a click, automatically pinpointing all of your assets and populating a network asset list. The platform then goes into learning, conducting a detailed analysis of all network interactions over a 30-day period and providing unparalleled visibility into assets and dependencies.  
• Automated Tagging and Policy Creation: Gone are the days of manual labeling, guessing on grouping, and never-ending policy creation and management. Using the data gathered in learning, Zero Networks generates deterministic, fine-grained policies that reflect the organization’s unique needs.  
• Effortless Enforcement: Once policies are in place, the platform automatically segments assets, maintaining security without disrupting day-to-day operations.  

It’s a streamlined process that not only simplifies implementation but also reduces the likelihood of human error, a common issue with traditional network segmentation techniques like VLANs.  

Unlike traditional segmentation methods, which rely on static configurations and manually crafted rules, Zero’s automation-first approach enforces policies that are both precise and scalable, empowering security teams to stay ahead of evolving threats while minimizing operational overhead. By integrating segmentation into a broader Zero Trust strategy, organizations can confidently build networks that are resilient, efficient, and prepared for the future. Request a demo to learn more.