Firewall protection is the use of network security controls that monitor and restrict traffic between EV chargers, site networks, and backend systems to reduce cyber risk and prevent unauthorized access. In EV charging infrastructure, firewall protection helps ensure chargers can communicate with the CPMS and required services while blocking unnecessary inbound connections and limiting lateral movement within a site.
What Is Firewall Protection?
A firewall is a security control that applies rules to allow or block network traffic based on:
– Source and destination IP addresses
– Ports and protocols (TCP/UDP)
– Connection state (established vs new)
– Application-level inspection (in next-generation firewalls)
Firewall protection can be implemented at different layers:
– In a site router or gateway
– In a corporate IT perimeter firewall
– In a cloud environment protecting CPMS services
– On-device firewall rules (where supported)
Why Firewall Protection Matters for EV Charging
EV chargers are connected devices and can be targeted through the network if exposed.
– Prevents unauthorized access to charger management interfaces
– Reduces risk of malware propagation and lateral movement across site networks
– Protects CPMS connectivity and reduces operational disruption from attacks
– Helps meet cybersecurity expectations in tenders and due diligence
– Improves resilience by enforcing consistent, predictable connectivity patterns
– Supports incident containment if a device or network segment is compromised
Typical Firewall Objectives for Charging Sites
– Allow only required outbound traffic from chargers to the CPMS
– Block inbound internet traffic to chargers unless explicitly required and secured
– Segment charger networks from corporate and critical building systems
– Restrict management access to authorized maintenance networks only
– Log traffic for troubleshooting and security monitoring
Common Firewall Protection Patterns in EV Charging
Default-Deny Inbound, Allow Required Outbound
Most chargers only need outbound connectivity to:
– CPMS endpoints (often via secure TLS connections)
– Time synchronization (NTP)
– DNS resolution
– Optional: firmware update services and certificate enrollment endpoints
Firewall rules should be tight and documented to reduce the attack surface.
Network Segmentation
Segment EV chargers into their own network zone.
– Separate VLAN for chargers
– Firewall rules that prevent chargers from reaching internal corporate networks
– Only allow traffic to approved services (CPMS, monitoring, update servers)
Segmentation helps ensure a compromised charger cannot access business-critical systems.
Secure Remote Maintenance Access
If remote service access is needed:
– Use VPN access with strong authentication
– Restrict access to specific management ports and only from trusted IPs
– Time-bound access windows for maintenance
– Audit logging of administrative sessions
Avoid exposing charger management interfaces directly to the public internet.
Site-to-Cloud Security Controls
Operators often secure CPMS and cloud services with:
– IP allowlists for trusted gateways
– Web application firewalls (WAF) for portals and APIs
– Rate limiting to reduce abuse and denial-of-service risk
– DDoS protection services (platform-dependent)
Practical Firewall Considerations for EV Charging Deployments
– Corporate IT policies may block required ports or TLS inspection may break secure device connections
– Cellular deployments may use private APNs or VPN tunnels to reduce exposure
– Consistent rule templates reduce errors across multi-site rollouts
– Logging and monitoring are essential: connectivity issues often look like “charger faults” but are firewall blocks
– Firewall policies should align with certificate-based authentication and secure update workflows
Best Practices
– Maintain a documented list of required endpoints and ports per charger model and CPMS
– Use least-privilege rules: only what is necessary, nothing more
– Segment chargers away from building management systems (BMS), POS systems, and corporate LANs
– Use secure DNS and reliable NTP to prevent time drift and log issues
– Monitor firewall logs for repeated blocks, scanning attempts, and abnormal traffic patterns
– Include firewall validation in commissioning: “charger connects and remains stable for X hours”
– Plan for firmware and certificate lifecycle: update endpoints must remain reachable
Common Mistakes to Avoid
– Placing chargers on a flat corporate LAN with broad access
– Allowing inbound access from the internet to chargers without VPN and hardening
– Blocking NTP/DNS, causing time drift, failed logs, and unstable CPMS sessions
– TLS interception that breaks secure charger-to-CPMS communication
– No logging, making outages hard to diagnose
– Inconsistent rules across sites, leading to unpredictable uptime
Limitations to Consider
– Firewall protection does not secure a charger if credentials are weak or firmware is unpatched; it is one layer
– Overly strict rules can cause intermittent connectivity and false downtime if not tested
– Some third-party integrations (payments, roaming) may require additional endpoints and careful rule management
– Multi-tenant buildings may restrict network changes, requiring cellular/VPN alternatives
– Security ownership must be clear: site IT vs operator vs OEM responsibilities
Related Glossary Terms
EV Charging Cybersecurity
Network Segmentation
Data Encryption
Secure Update Pipeline
Device Authentication
Device Certificate Enrollment
CPMS
Intrusion Detection