What is Network Segmentation?

Network segmentation is a cybersecurity approach that separates corporate networks into smaller, more manageable segments or subnetworks to protect users, sensitive information, and critical systems.

ben kazinik

04.06.2023

8 min read

Each segment contains a specific group of devices or resources that have similar security or operational requirements, and network traffic can be controlled or limited between those segments.

Segmentation deters threat actors looking for the easiest access route, allows organizations to apply security controls and policies more effectively, and improves network performance.

What is Micro-Segmentation?

Network segmentation is sometimes confused with micro-segmentation. Both processes work to decrease an organization’s attack surface and secure network resources, but network segmentation and micro-segmentation have different purposes.

Regular network segmentation refers to dividing a network into larger segments based on departments or functions such as sales, marketing, and accounting. 

Micro-segmentation goes a step further, creating even smaller, isolated segments at the workload level. For example, micro-segmentation offers a way to secure IoT devices by creating dedicated segments for their use and applying stringent security controls to prevent unauthorized access to them and limit their ability to interact with other parts of the network.

With micro-segmentation, fine-grained security controls can be applied to individual devices, workloads, or applications. This provides IT teams with more precise access controls and monitoring capabilities – for faster, more reliable threat detection and response.

How Does Network Segmentation Work?

In network segmentation, different segments are isolated from one another through the use of network devices such as routers, switches, or firewalls, which act as barriers between them. Each segment or zone is managed separately, and policies specifying how they can be used are applied individually. 

This isolation prevents unauthorized access or lateral movements of threats within the network, so if bad actors are able to infiltrate one part of the network, it doesn’t mean they’ll have access to everything.

There are several steps involved in the segmentation process, including:

1. Identify Segmentation Criteria: Networks may be customized and divided according to departments, functions, security requirements, or other relevant factors that make sense for the organization.
2. Create Segments: Segments are created with devices like routers and switches, ensuring traffic flows appropriately between them.
3. Assign IP Addresses: A unique range of IP addresses is assigned to each segment to differentiate each one. Devices within the same segment can communicate with each other.
4. Implement Access Controls: Administrators must define each segment’s necessary access policies and restrictions. These policies specify which devices or users can access resources within that segment.
5. Control Traffic Flow: The network routers and switches examine the source and destination IP addresses of incoming packets and use predefined rules and routing tables to determine how to forward traffic.
6. Monitor and Manage the Network: The IT team can monitor each segment independently, which allows them to address issues more efficiently and simplifies network management tasks.

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Advantages of Network Segmentation

Network segmentation is a crucial strategy for enhancing network security. It offers several benefits for businesses that need to reduce the risk of unauthorized access or data breaches and ensure the availability of critical resources.

Better Operational Performance

Configuring your network into multiple segments improves network performance by reducing congestion and optimizing traffic flow. By dividing the network into smaller segments, organizations can prioritize and manage network traffic more efficiently, leading to faster and more reliable communication between departments and devices.

This leads to smoother and faster communication between devices within the same segment.

Limiting Cyberattack Damage

Network segmentation reduces the overall attack surface of the network by breaking it into smaller, more manageable segments. It limits the potential impact of a security breach by containing threats within a specific segment and making it difficult for attackers to access all network devices.

Protecting Devices

If a device within a segment is compromised or infected with malware, the segmentation helps contain the threat within that segment. It also prevents the lateral movement of threats to other devices within the segment.

Coinciding application control policies can also prevent unauthorized access to other devices on the network. By customizing security measures for each segment, devices receive enhanced protection corresponding to their level of sensitivity.

Reducing Compliance Scope

In industries like banking, health, and finance, organizations may need to apply policies or implement security measures to specific parts of their network, based on compliance regulations.

Network segmentation can reduce compliance scope by allowing organizations to implement customized security measures for each segment based on its specific requirements. That means sensitive data can be stored in a highly secure segment while less sensitive resources can be placed in a less secure segment. 

Better Performance

IT administrators can allocate more bandwidth to high-priority segments that handle critical business functions like VoIP communications to ensure their operations run smoothly.

Conversely, they can allocate less bandwidth for lower-priority segments like print servers. This optimized bandwidth allocation prevents bottlenecks and ensures that critical applications or services receive the necessary resources, improving operational performance.

Trust vs Zero Trust in Network Segmentation

A trust-based approach applies a default level of trust to devices and users within the network. It assumes that anything internal to the network is trustworthy, and considers anything external to be untrusted.

Under this model, once a device or user gains access to the network, they are typically granted certain privileges and have relatively open access to resources within the network. Trust-based segmentation relies on perimeter-based security, such as firewalls, to protect the network from external threats.

In contrast, a zero-trust approach assumes that no device or user should be inherently trusted, regardless of their location within or outside the network. It challenges the notion that internal resources are automatically secure.

Zero trust segmentation adopts a more granular and strict approach to access control and requires devices and users to continuously prove their trustworthiness before accessing network resources. This is achieved through mechanisms like strong authentication, device health checks, and authorization controls. 

Types of Network Segmentation

Every business network has unique segmentation needs. Organizations need to consider the types of data and users they need to protect when selecting the appropriate network segmentation type for their situation. 

Virtual Local Area Networks (VLAN) Segmentation

VLAN segmentation involves dividing a physical network into separate logical or virtual networks (VLANs). Organizations can isolate and control the communication between devices within each VLAN, enhancing network performance and security.

Software-Defined Networking (SDN) Segmentation

SDN segmentation uses software to create virtual network segments, allowing for dynamic and flexible management of network resources and policies. SDN allows IT teams to define and enforce policies that regulate traffic flow and access within each network segment, improving security and helping businesses to adapt to changing needs as they grow.

Firewall Segmentation

Firewall segmentation refers to the use of firewalls to create distinct security zones or segments within a network, controlling the flow of traffic between segments based on predefined security policies. This enhances network security by restricting unauthorized access and preventing the spread of threats.

Network Segmentation Techniques

There are two main ways to segment your network.

Perimeter-based segmentation

Physical or perimeter-based segmentation relies on physical hardware and arms each section with its own internet connection, network cabling, and firewalls. Perimeter-based approaches do not require the high level of zero-trust security other methods use, so they offer less security.

Once hackers or malicious actors manage to breach the firewall, they can freely navigate within the network, encountering few obstacles.

Network virtualization

With the increasing prevalence of remote work, geographically dispersed teams, and cloud networking, organizations have had to adopt cloud security measures that go beyond physical boundaries in order to safeguard numerous endpoints. This is where network virtualization comes into play.

Virtual network segmentation extends across the entire network rather than protecting only the perimeter. In the case of a breach, virtualized networks make it easier to secure network segments and prevent further damage.

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Network Segmentation Examples

Every business that stores data digitally and accesses the internet needs to incorporate segmentation into its overall cybersecurity strategy, though levels of segmentation will vary from one organization to the next.

When deciding how to segment your network and determine what zones are important for your situation, you’ll need to consider the types of data you’re dealing with and the role of each user.

Reflect on which data will be most important for which users to access to perform their duties. For example, you may wish to create individual segments or zones such as:

• Guest Network: A guest network allows guests to access the internet without gaining access to private or sensitive company data.
• Individual Departments: Each department is assigned its own network segment with specific security policies and resource allocation. This isolates departmental activities and resources and prevents unauthorized access or interference between departments.
• User Groups: Zones are created based on user roles, access privileges, or security requirements. Users with similar roles or permissions are grouped together in specific network segments, allowing for customized access controls and security policies — ensuring that users only have access to the resources they need.
• Communication Systems: Segments can be dedicated to specific communication systems like VoIP phone systems or video conferencing. This allows focused security controls and ensures reliable and secure communication while limiting network vulnerabilities.
• IoT Devices: Specialized zones for IoT devices like smart lighting, security cameras, or industrial equipment keep them isolated from other network resources and reduce the risk of network compromise.
• Customer Databases: Housing customer data in its own segment means strict access controls and encryption can be applied, and sensitive information can be monitored. It also helps ensure regulatory compliance and mitigates the risk of data leakage.

Network Segmentation Best Practices

Here are a few key segmentation practices to use in your business.

Maintain Balance

It’s important to strike a balance between the level of network segmentation and the operational needs of the organization to ensure both security and efficient connectivity.

Monitor and Audit Networks

Regularly monitoring and auditing network activity helps detect and address potential security breaches, vulnerabilities, or policy violations.

Limit Third-Party Access Points

Minimize the number of entry points for external entities to reduce the risk of unauthorized access and potential security threats. For example, ensure your public-facing website is in a different segment from your sensitive corporate resources.

Create an Inventory of Your Assets

Before deciding what zones to create and what policies to apply, it’s important to identify and categorize the critical or sensitive data and resources that need to be protected.

Group Assets by Similar Networks

Grouping similar assets together in a single segment allows for focused security measures and efficient management of resources with similar security requirements.

Invest in Endpoint Security and Protection

Implement a robust endpoint security solution to safeguard individual devices, reduce the risk of compromise, and provide an additional layer of defense for the network.

Embrace Zero-Trust and Least Privilege

Adopt a zero-trust approach and implement the principle of least privilege to ensure that users and devices only have access to the resources they specifically need. This enhances security and minimizes the potential impact of a security breach.

Set Up Access Control Policies

Very few people should have access to the entire network. To reduce the risk of data being compromised, users should only be able to access the data they need to do their jobs.

Audit and Review Your Network Segments Regularly

As businesses and industries grow and evolve, administrators should evaluate the effectiveness of their network segmentation periodically, making segment adjustments and updating security policies as needed.

Make Legitimate Paths Easy to Follow

Establish clear and well-defined pathways for authorized network traffic to simplify the network design, improve operational efficiency, and help identify and prevent unauthorized network activity.

Perimeter 81 Can Simplify Your Network Segmentation

Many businesses in today’s cloud-centric environment rely heavily on cloud applications and security solutions to keep their networks protected and connected. Configuring your network to meet digital demands doesn’t have to be complicated.

Perimeter 81’s Network-as-a-Service (NaaS) solution takes the complexity out of managing your network. It provides the tools you need to manage, monitor, and secure all your users, devices, and resources from a single dashboard with flexible subscription-based pricing.

Request a demo to see what’s included.