FCSS_NST_SE-7.6 Exam Dumps - Fortinet Certified Solution Specialist Questions and Answers

The debug flow message iprope_in_check() check failed, drop specifically indicates a failure in the Local-In Policy check. The "iprope" (IP ROouting Policy Enforcement) engine handles policy lookups. The _in_check suffix confirms that the decision is regarding traffic destined to the FortiGate itself (Local-In traffic), rather than traffic passing through it.

D. The packet was dropped because the requested service is not enabled on FortiGate:

This is the most common cause. When a packet arrives destined for the FortiGate's interface IP (e.g., an HTTPS or SSH request), the kernel checks if that specific service is enabled in the interface settings (set allowaccess). If the service is not enabled (e.g., trying to Ping an interface where PING access is disabled), the iprope_in_check function fails and drops the packet immediately.

C. The packet was dropped because the trusted host list is misconfigured:

Even if the service (e.g., HTTPS) is enabled on the interface, the FortiGate checks the Administrator settings. If Trusted Hosts are configured, the source IP of the incoming packet is compared against the allowed list. If the IP is not on the list, the Local-In policy check (iprope_in_check) fails, and the packet is dropped to secure the management plane.

Why other options are incorrect:

A: If traffic is dropped by a standard Firewall Policy (traffic passing through the device from one interface to another), the debug message will typically state denied by policy x or no matching policy. It would generally be a forward check (iprope_fwd_check or similar), not an _in_check.

B: If there is no route to the source, the error is a Reverse Path Forwarding (RPF) failure. The debug flow logs this explicitly as reverse path check fail, drop.

The administrator cannot see traffic in the sniffer because it is being offloaded to the NPU (NP6). To view the traffic, offloading must be disabled so packets pass through the CPU.

B. config firewall policy ... set auto-asic-offload disable: This is the recommended method to troubleshoot specific traffic. By disabling ASIC offloading in the relevant firewall policies (Policies 5 and 17 in the exhibit), traffic is forced to the CPU and becomes visible to the sniffer.

C. diagnose npu np6 fastpath disable 1: This command temporarily disables the fastpath processing on the specific NP6 processor (ID 1) handling the ports. This forces all traffic handled by that NPU to the CPU, allowing the sniffer to capture it.

Incorrect Options: Option A uses invalid syntax (port-list disable is not a valid command). Option D (config system npu) is not the standard method for granular troubleshooting.

Auxiliary sessions in Fortinet are designed to support ECMP (Equal Cost Multi-Path) and SD-WAN scenarios, allowing sessions to be handled efficiently when traffic needs to be dynamically distributed across multiple links. With the auxiliary session setting enabled, FortiGate creates additional session table entries for each possible path in ECMP or SD-WAN—meaning that if the routing path changes (such as a link failover), a new session can be immediately activated and offloaded to the NP6 network processor for acceleration, ensuring minimal disruption. This greatly benefits high-throughput deployments.

Official documentation specifies that when auxiliary sessions are enabled, FortiGate doesn’t just rely on dynamically creating new sessions after a routing event, it proactively creates sessions for all potential paths. This means that in the event of a route change, two sessions exist and the traffic is quickly re-routed and offloaded, maximizing performance and reliability. Without this feature, multiple paths cannot be efficiently offloaded, and routing changes trigger a single session update, reducing failover performance.