Network segmentation is an essential security measure that involves dividing a computer network into smaller, isolated segments or subnetworks. Each segment, also known as a network zone or a security zone, contains a specific group of resources or systems with similar security requirements. The primary purpose of network segmentation is to improve security and enhance the overall network’s resilience. Here are some key reasons why network segmentation is necessary:

1. Security Isolation: If an attacker gains access to one segment of the network, they will have a harder time moving laterally to other parts of the network, limiting the impact of potential security breaches.
2. Access Control: This helps restrict unauthorised access and minimizes the attack surface by only giving users access to the network resources they need.
3. Containment and Mitigation: By isolating affected segments, the spread of threats can be limited, preventing them from affecting the entire network. It also enables faster identification, response, and remediation, as the affected segment can be addressed separately without disrupting other parts of the network.
4. Performance and Optimisation: Segmentation can improve network performance by segregating network traffic into different segments, administrators can prioritise critical applications, allocate bandwidth efficiently, and reduce network congestion.
5. Compliance and Regulatory Requirements: Many industries and organisations have specific compliance and regulatory requirements related to data privacy and security. Network segmentation can help meet these requirements by providing logical and physical separation of sensitive data and systems, making audits and compliance assessments more manageable.
6. Support for Different User Groups: Network segmentation allows organisations to create separate segments for different user groups, such as employees, guests, contractors, or partners. Each segment can have its own security policies and access controls tailored to the specific needs of that user group, enhancing security, and simplifying network management.