Implementing network segmentation for PCI DSS: a practical guide for UK SMEs

### Executive summary This article provides practical, non-technical guidance for UK small and medium-sized enterprises on implementing and maintaining network segmentation to protect the cardholder data environment (CDE) for PCI DSS compliance; it emphasizes starting with scoping and data-flow mapping, using simple VLAN/firewall-based separation, restricting administrative and remote access, validating segmentation through testing and monitoring, and keeping documentation and controls aligned as the business changes.