What Is Network Segmentation, and Common Segmentation Strategies

Network segmentation breaks the network into discrete segments with defined boundaries. Next-generation firewalls (NGFWs) or similar security solutions inspect traffic attempting to cross these boundaries, which can identify malicious content and apply access controls.

Network segmentation can enhance network security and performance. By inhibiting lateral movement of threats through the network, it reduces the likelihood of a successful attack. Additionally, performance can be enhanced by segment-specific optimizations and preventing unnecessary traffic from crossing segment boundaries.

What are the benefits and use cases of network segmentation?

An organization can use network segmentation to achieve various goals, including:

• Enhanced Security: Network segmentation restricts the movement of threats through the network. This improves security by reducing the risk that attackers will achieve their goals and improving their probability of detection.
• Improved Performance: Segmentation restricts traffic flow through the network. This can help improve architectural design by reducing the distance between communicating systems and reducing unnecessary traffic.
• Simplified Compliance: Regulations such as PCI DSS mandate that systems with access to sensitive data have specific controls and undergo regular audits. Network segmentation reduces the scope of compliance by isolating these systems from the rest of the network.
• Easier Management: Segmentation breaks the network into multiple, smaller pieces. This makes it easier to design and apply policies for each segment.

Common network segmentation strategies

Network segmentation involves breaking the network up into several different pieces. This can be accomplished in a few different ways, including:

Physical Segmentation

Physical segmentation implements network segmentation at the hardware level. When designing the physical network layout, the different segments are defined as separate subnets connected to the rest of the network via their own gateway, which monitors and controls network traffic.

The main benefits of physical segmentation are that it is easy to understand and implements strong segmentation between subnets. However, implementing it is more costly and less flexible than other options.

Logical Segmentation

Logical segmentation implements network segmentation at the software level using solutions such as virtual local area networks (VLANs). While systems in different segments may be physically connected to one another, they can’t communicate except via the routes defined in the software.

Logical segmentation is generally more cost-effective and flexible than physical segmentation since it overlays an organization’s existing physical infrastructure. However, an improper configuration may undermine its security and allow unauthorized access across segment boundaries.

Micro-Segmentation

Micro-segmentation is a form of software-based segmentation that divides a network into individual workloads. Its purpose is to allow highly granular control over east-west data flows within an organization’s environment.

Micro-segmentation offers highly tailored security and is a good fit for sprawling, multi-cloud environments. However, implementing and managing can be more complex due to the need for an in-depth understanding of applications’ dependencies and traffic flows.

Best practices for network segmentation

Network segmentation can offer significant benefits to the business if implemented correctly. Some best practices to guide the process include:

• Determine Business Needs: Network segmentation can be implemented for various purposes, such as enhancing security or improving performance. Defining business needs will help to identify the best form of segmentation and how to divide the network.
• Map Network Infrastructure: Effective network segmentation requires understanding the purpose of an organization’s applications and the traffic flows between them. For example, an application and the core database it depends upon should likely be in the same segment.
• Define Segment Boundaries: A network segment should include systems with similar business roles and levels of trust. After mapping network infrastructure and workflows, segments should be implemented accordingly.
• Implement Least Privilege: Least privilege access means that users, applications, and devices don’t have access or privileges that aren’t needed for their role. Least privilege complements network segmentation by reducing the risk that an attacker can do damage within a segment or cross segment boundaries.
• Perform Continuous Monitoring: Network segmentation enhances visibility into traffic flows within an organization’s network. Continuous monitoring allows the business to use this information to detect and remediate threats quickly.
• Review Segments Regularly: Segment boundaries should be defined based on the business’s needs. Regular audits enable the organization to identify whether segments should be updated to serve the organization better.

Network segmentation vs VLAN

Network segmentation is a security practice, while VLANs are a means of implementing that practice. More specifically, VLANs are a common method of implementing logical segmentation. NGFWs, routers, and other network infrastructure can label traffic as belonging to a particular VLAN and prevent cross-VLAN traffic except at the defined boundary, even if traffic flows over the same physical links.

Network segmentation vs subnetting

A subnet is a section of a network with its own allocated IP address range. Subnetting is part of physical segmentation because each segment is its own subnet that connects to the rest of the network via a gateway. All traffic flowing out of a subnet goes through the gateway, which can implement the access and other security controls associated with network segmentation.

FAQ

What is an example of a network segment?

A network segment is a group of computers within a network that are partitioned from the rest of the network. For example, many organizations have a guest network that visitors can connect to but cannot access the rest of the network.

What are the challenges of network segmentation?

Challenges of network segmentation include defining the proper boundaries and ensuring that they’re enforced. Ideally, network segmentation will have minimal impact on legitimate business while making it more difficult for attackers to achieve their goals. The organization also needs to ensure that attackers can’t bypass the segmentation and gain unauthorized access to resources.

What is the difference between network segmentation and isolation?

Isolation can be seen as a more extreme form of segmentation. Network segmentation breaks the network into pieces, but different segments can communicate with one another via defined gateways. A device or segment that is isolated may not be able to communicate with the rest of the network at all.

Segment Your Network with Cato’s Secure Access Service Edge (SASE) Solution

Network segmentation divides the network into discrete pieces, placing trust boundaries between them. Since all traffic crossing these boundaries is inspected, an organization gains increased visibility into and control over east-west traffic within its network.

Cato SASE Cloud integrates zero-trust network access (ZTNA) capabilities, which intrinsically implement micro-segmentation within the corporate WAN. With SASE, organizations can easily implement zero-trust policies and prevent the lateral movement of threats within their networks. Contact us to learn more about how Cato SASE Cloud can help your organization achieve its network segmentation goals.