Network Segmentation: 8 Best Practices & 6 Benefits in 2025

Network security statistics show that ~90% of organizations have reported at least one data breach or cyber incident. Companies continue to invest in network segmentation tools to enable finer-grained network zones against data breaches.

Security executives should explore network segmentation examples and network segmentation applications to understand how to secure their network resources.

8 best practices of network segmentation

Learn more about cybersecurity best practices.

1. Define security zones

Organizations can define security zones (logical groupings) of network assets that share similar security requirements and access controls. Each zone can be isolated from others to enforce appropriate access policies. Typical types of network segments:

• DMZ (demilitarized zones)
  • Purpose: Create a subnetwork containing your organization’s publicly accessible services.
  • Typical Components: Web servers, or email servers.
• Internal network zones
  • Purpose: Protect sensitive internal resources and data.
  • Typical components: File servers, application servers, internal databases, corporate workstations.
• Management zones
  • Purpose: Segment administrative traffic from regular network traffic.
  • Typical components: Network management systems, administrative consoles, logging servers.
• Restricted zones
  • Purpose: Host sensitive data and systems requiring high-security measures.
  • Typical components: Financial systems, or intellectual property databases.

2- Define and classify network assets

Companies can assess their resources and attribute values with network segmentation constraints. Each resource (applications, IoT (internet of things) devices, databases) can be classified based on category, and risk priority.

• Inventory assets: Create a comprehensive inventory of all network assets, including servers, endpoints, applications, and data.
• Classify assets: Classify assets based on sensitivity, criticality, and compliance requirements. For example, separate confidential data from general business data.

3. Apply microsegmentation

Companies should use microsegmentation to restrict network access at smaller tiers:

• Fine-grained microegmentation: Use microsegmentation tools to create highly granular security policies, often at the workload or application level, to further minimize the attack surface.
• Software-defined perimeter (SDP): Leverage SDP software to segment Internet-connected infrastructure (servers, routers, etc.) so that external parties and attackers cannot see it.

The following technologies help companies leverage microsegmentation and zero trust network access: 

• Software-defined perimeter
• Secure web gateways
• Firewalls

4- Limit third-party access

75% of IT users say that data breaches result from providing highly-privileged access to third parties.¹ Creating distinct gateways with specific security measures for each user is critical for isolating third-party access to minimize data leaks. Companies should:

• Least privilege principle: Apply the principle of least privilege to restrict access to only what is necessary for each user or device.
• Network access control (NAC): Use NAC solutions to enforce security policies and manage access to the network based on user roles and device compliance. 

5- Monitor and audit networks in real-time

To eliminate the gaps or weaknesses in the network, all segmentation operations should include continuous monitoring and auditing of network traffic and activity. 

• Network monitoring: Use network monitoring tools to detect and respond to threats, unauthorized access, and malicious activity.
• Logging: Continuously log network traffic to detect anomalies and potential security incidents (e.g. intrusion, password changes).

6- Avoid over segmentation

Over-segmentation can lead to unnecessary complexity, management challenges, and performance issues. Here are some best practices to prevent over-segmentation:

• Right-sized segmenting: Ensure segments are appropriately sized to balance security with manageability and performance. Control network segment zones and avoid making segments too small unless necessary.
• Functional grouping: Group assets based on functional roles rather than creating overly granular segments. For example, group all web servers in one segment rather than each server in its segment.

7- Automate cybersecurity practices

Manually doing all of these tasks may be impracticable. Cybersecurity automation is a useful instrument for detecting cyber threats or vulnerabilities, streamlining workloads, and recognizing new assets added to the network while implementing network segmentation. Organizations can use:

• Patch management: Regularly update and patch all systems and devices within each segment to protect against vulnerabilities.
• Software-defined networking (SDN): Use SDN controllers to automate segmentation based on traffic patterns, security requirements, and business policies.

8. Test and validate segmentation

Organizations can leverage several methods to ensure that the segmentation policies are correctly implemented:

• Network mapping tools to perform:
  • Networks scanning: Scan the network to identify active devices, open ports, and services running on each segment.
  • Validation: Ensure that devices are correctly segmented and that there are no unintended connections between segments.
• Penetration testing: Test for vulnerabilities within the network and verify that segmentation prevents lateral movement.
• Firewall and ACL verification: Automatically verify that firewall rules and access control lists (ACLs) are correctly configured

Real-life case study: Network segmentation saved TeamViewer from APT29 phishing attack

TeamViewer is a remote access and control computer software that enables the repair of computers and other devices.

What happened: APT29, a cyber-espionage group accessed TeamViewer’s corporate network to exfiltrate internal customer data.

However, the threat actors had limited access to the company’s internal IT network due to “strong segmentation” between its environments.

Result: TeamViewer kept all servers, networks, and accounts separated. The company also created granular network zones with several levels.

This helped block unauthorized access to migrate lateral data flows and protect customer data from the APT29 attack.²

6 benefits of network segmentation

1- Improve cybersecurity risk management

Segmentation can neutralize attacks with mobility limits by defining barriers between distinct sub-segments. This granular approach improves cybersecurity risk management by preventing hackers from moving laterally once they have breached the network. 

2- Increase network visibility

Network segmentation creates subnets (a network inside a network) where traffic may move a shorter distance without passing through unnecessary routers. This makes it easier to monitor vulnerabilities and detect the most common cyber attack vectors compared to a larger network because of its limited reach.

3- Protect physical devices

Segmentation can prevent risky traffic from physical devices such as facility control systems (e.g. gauges, manufacturing equipment). OT network segmentation can prevent potentially risky Internet traffic from accessing these systems.

4- Limit cyberattack damage

Segmentation helps cybersecurity by restricting the movement of an attack. For example, network segmentation prevents malware from laterally spreading across the network and infecting other devices.

5- Build IT governance:

Network segmentation transforms security policies into a structural format, providing transparency into current compliance failures and enabling risk-based detection for network components.

6- Compliance

Network segmentation helps operationalize compliance initiatives in these domains:

• Data classification: Classify data based on sensitivity (e.g., confidential, personally identifiable information, public) to determine appropriate segmentation levels.
• Risk assessment: Conduct a risk assessment to identify critical assets, systems, and applications that require segmentation to mitigate specific risks.

What is network segmentation?

Network segmentation is a defense-in-depth security mechanism that divides the main network into several, smaller subnetworks to limit a cyber attacker’s activity by minimizing lateral network movement.

Each subnetwork or “zone” represents an extra layer of security (e.g. microsegmentation, role-based access control (RBAC), zero trust network access (ZTNA)), with its access point, username and password, and firewall protection. 

Read more: Network segmentation vs microsegmentation.

Physical vs logical network 

Network segmentation can be classified under two major categories: physical and logical network segmentation.

• Physical network: A physical network refers to the actual hardware components that connect devices, such as wires, routers, endpoints, hubs, switches, and other physical structures. 

• Logical network: A logical network applies to how data is transported between devices and how they are structured and controlled Logical networks can be controlled by setting network protocols. 

Learn more about Internet of Things (IoT) cybersecurity.

How does network segmentation work?

Network segmentation separates a network into many portions, each of which may be controlled differently. This technique is often carried out by adopting one of two approaches: physical segmentation or logical segmentation.

1- Physical segmentation 

Physical segmentation is dividing a large computer network into smaller subnets. For example, a physical or virtual firewall can operate as the subnet gateway, regulating which traffic enters and exits the network. 

Functionality: Because the layout is set in the design, physical segmentation is simple to manage, however, it is economically expensive, less flexible, and scalable since the company must purchase, deploy, and manage actual hardware on-premises.

2- Logical segmentation

Logical segmentation is using software to divide a network into smaller sections by subnetting. Logical segmentation creates subnets using two major methods: virtual local area networks (VLANs) or network addressing schemes. 

Functionality:  Logical segmentation is far more adaptable than physical segmentation. Logical (e.g. VLAN) segmentation methods are less costly and more flexible since these approaches allow users to set up automated security configurations or redesign the network without purchasing new equipment.

Why should organizations consider implementing network segmentation?

Network segmentation is an effective instrument for preventing outsiders (e.g. customers, vendors, malicious attackers, or any unauthorized user) and protecting static IP addresses, whether third parties, from accessing sensitive data such as personal data or corporate accounting files.

The following are some of the reasons for implementing network segmentation:

• Massive networks are divided into smaller, more manageable sections.
• Security operators can create specific rules for each subnet.
• Some parts of the network can experience reduced user traffic, leading to increased network performance.
• Improves security in terms of minimizing how far a harmful attack may move, by constraining network threat (e.g. ransomware) into a single segment.

Further Reading

• Top 10 Microsegmentation Tools 
• Role-based access control (RBAC)
• Top 10 Insider Threat Management Software
• Microsegmentation: What is it? Benefits & Challenges
• Zero Trust Network Access (ZTNA): Definition & Benefits
• 10 Cybersecurity Best Practices for Corporations

External Links

• 1. Survey: Managing third-party permissions is ‘overwhelming’ | Ponemon-Sullivan Privacy Report.
• 2. Network Segmentation Saved TeamViewer From APT29 Attack. Dark Reading