What is network segmentation and its benefits and typical methods to implement it?

• A. Divides networks into zones (DMZ, internal networks) to limit lateral movement; uses VLANs, firewalls, access control lists, and microsegmentation
• B. Combining all assets into a single flat network
• C. Segmentation is only about physical layout.
• D. Segmentation eliminates the need for access control.

Answer: (B)

Network segmentation is the practice of breaking a larger network into smaller, isolated parts so traffic between parts is tightly controlled. This creates defined boundaries that limit how far an attacker can move laterally if a device is compromised, makes security policies easier to enforce, and helps contain incidents. It also improves performance by reducing unnecessary broadcast traffic and simplifies management.

A practical way to implement segmentation is to create zones such as a DMZ for public-facing services and an internal network for sensitive assets. You achieve the separation with VLANs to keep traffic apart at the data-link layer and subnets to separate it at the routing layer. Boundaries between segments are then protected with controls like firewalls and access control lists, which specify what traffic is allowed to move between zones. Modern approaches add microsegmentation, applying precise, software-defined security policies to individual workloads or services, so even within a data center or cloud environment, no part of the network is inherently trusted.

So the best description is dividing networks into zones and using methods like VLANs, firewalls, ACLs, and microsegmentation to enforce the boundaries. The idea of a single flat network contradicts segmentation, and segmentation isn’t limited to physical layout or to removing the need for access control.