FortiGate Firewall & FortiOS

Practical help articles for common problems.

Check the management interface address, network reachability, and HTTPS management access allowed by your organization.

Use approved device recovery procedures and verify ownership before attempting any recovery operation.

Review source and destination interfaces, address objects, service definitions, policy order, and matching logs.

Check WAN link status, default routes, DNS, and relevant firewall policies before changing configuration.

Compare DNS results from a trusted client and firewall and verify configured resolvers and routing.

Review performance metrics, traffic patterns, and system logs to identify sustained resource pressure.

Confirm hardware support, upgrade path, release notes, configuration backup, and maintenance window.

Record the exact error and installed version, preserve backups, and follow version-specific recovery guidance.

Check cabling, negotiated speed, interface counters, and switch port logs.

Check interface DHCP settings, available leases, VLAN tagging, and competing DHCP servers.

Review matching policy, source NAT mode, destination NAT, and upstream routing.

Inspect the matching policy and category logs, and request an authorized policy review.

Check heartbeat connectivity, cluster status, firmware compatibility, and monitored interfaces.