Understanding VMware NSX security concepts in practice

Looking for a breakdown of core NSX security concepts? Get to grips with the basics – and how VEDP courses can help.



VMware NSX is a software-defined networking and security virtualisation platform. Its main job is to abstract network functionalities away from physical hardware, with all the cost savings and operational efficiencies that brings.

These functionalities include core tasks like switching, routing, firewalling, load balancing and VPN.

As well as letting you do without physical hardware, NSX also enables security policies and network automation across complex cloud environments (private, public and multi-cloud).

It also allows systems administrators to use advanced security tools. These are flexible, cloud-based and highly capable tools built on the cybersecurity principle of "zero-trust security".

VMware's NSX's core security features include micro-segmentation and firewalling. So, what do these mean in practice?

In this article, we take a quick look at these essential concepts before exploring how VMware Education Delivery Partner courses can help IT professionals level up their NSX-pertise.

First of all, what do we mean when we talk about "micro-segmentation"?

What is micro-segmentation?

Imagine you have a million euro (or dollars, or pounds) in cash and you want to store it safely at home. One safe is a good start. But if the code is cracked, your money's gone. The best thing to do is to split that million between a variety of safes.

This is the simplest analogy for micro-segmentation. Networks are divided into small, isolated segments known as "micro-segments". These segments are workloads, applications and even devices.

This has two main benefits: one internal and one external. Internally, IT has greater control than ever over who has access to workloads.

Externally, cyber attackers are thwarted in their attempts to breach your network. Why? Because they no longer have one point of entry that can be smashed in with a digital crowbar. Instead, they now have to contend with a sea of isolated, contained segments.

Micro-segmentation is a key example of zero-trust security. This is a school of cybersecurity that believes every device and every user poses a potential risk to the network, both internally and externally.

This might sound like paranoia. But in the context of a business handling sensitive data (read: all businesses in 2026), this rigorous approach is invaluable.

Micro-segmentation is one of VMware's biggest contributions to the IT landscape. It was introduced to the market through the first version of NSX in 2013.

It replaces traditional network security methods such as VLANs and WANs, taking those big perimeter fences and turning them into endless boxes.

As well as micro-segmentation, VMware NSX relies on another powerful concept: the distributed firewall.

VMware NSX's distributed firewall

Distributed firewalls (DFWs) have been around since the late 1990s. They were introduced to address the problems faced by traditional perimeter firewalls – namely, their difficulty in handling internal traffic (also known as "east-west" traffic).

Today's distributed firewalls are more powerful than ever – and NSX's is a great example. It operates at the kernel level on every hypervisor and includes a Gateway Firewall for edge security.

As with micro-segmentation, the main benefit of a DFW is granularity, ensuring that security policies are followed consistently and all east-west traffic is secured.

Both the DFW and the Gateway Firewall are managed via the NSX Manager and cover all virtual, physical, containerised and cloud workloads.

Like all distributed firewalls, NSX's DFW replaces the perimeter-based, hardware firewalls of old. It takes security from a single checkpoint to a decentralised and software-defined model.

Advanced Threat Prevention

Advanced Threat Prevention (ATP) was introduced in the mid-2010s by security vendors seeking to help organisations combat sophisticated malware and zero-day threats.

ATP is central to NSX's security concepts. Here, it provides a comprehensive and multi-layered security approach, tackling all threats within the data centre, no matter how sophisticated.

It works by integrating distributed intrusion detection systems and intrusion prevention systems (IDS/IPS), network sandboxing, vDefend security services and network traffic analysis (NTA).

ATP improves the accuracy and reliability of security alerts, reduces false positives (false alarms) and secures east-west traffic. The result? A faster and more accurate form of threat prevention across all cloud networks.

Zero-trust security

In complex cloud environments, the attack surface is spread out. You might think this is a reason to rest on your cybersecurity laurels. In fact, cyber criminals are more advanced than ever, and the principle of zero-trust security has never been more relevant.

Zero-trust security is based on the principle "never trust, always verify". In practice, this means that users and devices have to be continuously authorised.

Gone are the days when staff could be logged in permanently. We live at a time when the network consists of multiple devices in multiple locations – so authentication has to be thorough and relentless.

It's another example of how cybersecurity has become more and more granular. Segments have become micro-segments, and each login attempt is given equal weight.

These principles aren't unique to VMware NSX – but they are central to an understanding of how NSX operates in the real world.

How we can help

Educators the world over will tell you that the best way to learn is on the job. You can't beat experience – but in the context of cybersecurity, experience can be hard to find.

That's because real-world experience of cybersecurity has real-world consequences – consequences that could cost a company time, money and headaches.

This is where VMware Education Delivery Partners (VEDPs) come into their own. They provide IT professionals with a sandbox environment where they can experiment with VMware products, including NSX, to their heart's content – and at no risk to their business's day-to-day operations.

Here at Ascend Cloud Solutions, we provide best-in-class lab hosting services for VEDPs.  So, if you're looking for VMware lab hosting services to bring your training to life, get in touch with Ascend Cloud Solutions today to find out why we're the best for the job.