VLAN isolation sounds great until you forget the firewall rules that actually make it work

VLANs are a powerful way to segment home networks and isolate IoT, guest, and security devices from trusted machines, but they only work as intended when paired with correct firewall rules. Without properly configured traffic policies, devices can intermittently lose access or behave unpredictably. A practical breakdown covers common VLAN categories (primary, IoT, security, homelab, guest), the pitfalls of misconfigured rules, and how platforms like Home Assistant require deliberate allow rules to reach smart home devices across VLANs.