Although it is only a recommendation for PCI DSS v4.0, effective network segmentation is a must to protect your digital realm from cyber threats like ransomware. Firewalls, routers and switches must be appropriately placed for network security control. Though far more complex than physical fire doors, these devices act similarly, as digital barriers that keep attacks at bay and prevent full-scale network disaster by stopping the spread of fires. Their effectiveness depends on vigilant updating and monitoring. Lapses may lead to breaches. New Operational Resilience regulations (eg CORA/DORA) also require organizations to protect their digital assets that support identified Important Business Services, by implementing effective digital fire doors.