FCSS_NST_SE-7.6 Fortinet NSE 6 - Network Security 7.6 Support Engineer Questions and Answers

The IKE_SA_INIT exchange in IKEv2 is responsible for DoS protection measures. During IKE_SA_INIT, before authentication and further exchange, the responder can use cookie challenges (per RFC 7296 and Fortinet VPN documentation). If a DoS attack is suspected (many requests from the same source), the responder replies with a cookie. Only after the initiator returns the correct cookie does the exchange proceed, protecting the responder from state exhaustion and certain forms of DoS traffic at the handshake stage.

The diagnose debug authd fsso server command is the primary tool for troubleshooting communication between the FortiGate and the FSSO Collector Agent. This debug output reveals the status of the connection and the reasons for failure. The three most common connectivity issues identified by this debug are:

FortiGate cannot reach the IP address of the collector agent (Option C): The debug will show connection timeouts or "host unreachable" errors if the Layer 3 connectivity is missing.

The connection was refused / Port mismatch (Option B): If the FortiGate can reach the IP but the Collector Agent is not listening on the specified port (default 8000), the debug will display "Connection refused." This often happens if the port configured on the FortiGate does not match the listening port on the agent.

The pre-shared key does not match (Option D): If the IP and Port are correct, the next step is authentication. If the password configured on the FortiGate does not match the one on the Collector Agent, the debug will explicitly show an "Authentication failed" or "password mismatch" error during the handshake.

Note on other options: Option A (SSL) is less common than basic connectivity/auth mismatches. Option E (Group filters) relates to user processing logic, which occurs after connectivity is established.

Parallel Path Processing (PPP) in FortiOS refers to the system’s ability to evaluate and select among multiple processing paths—often involving dedicated network processors, content processors, or CPU-based workflows—to optimally process packets. The official documentation highlights that the PPP engine dynamically selects which hardware or software path to use for each session based on session characteristics, policy configuration, and traffic type. This dynamic selection results in optimal throughput and resource utilization.

The document specifies that PPP assesses several processing paths in parallel, using decision logic to determine whether a session should be offloaded to specialist hardware (like NP6, CP9, etc.) or stay in the CPU path, ensuring that each packet is handled by the most efficient available method under current load and policy. Hardware and software configurations both influence this outcome, but it is the PPP engine's decision-making that defines the optimal path per session.

https://community.fortinet.com/t5/FortiGate/Troubleshooting-Tip-How-to-troubleshoot-FSSO-agentless-polling/ta-p/214349

From the snippet we can see that FortiGate (via the fssod daemon) is directly detecting the user logon rather than relying on a separate “collector” or “DC agent.” This indicates agentless polling—FortiGate polls the DC’s event logs over TCP 445 to discover logons. So: - FSSO is using agentless polling mode to detect logon events - In agentless mode, FortiGate will periodically poll the same IP (the DC) on port 445 to see if the user is still logged on

Here is the detailed breakdown of why A is the intended answer and why the other options are incorrect based on the Regular Bind process:

Analysis of Regular Bind (The Verified Process):

Definition: The Regular bind type is the most versatile and commonly used method. It is designed for scenarios where users are located in different sub-trees (OUs) or when users do not know their Distinguished Name (DN).

The "Four Steps" (Standard Correct Answer Description):

Admin Bind: The FortiGate binds to the LDAP server using a pre-configured administrator or service account (defined in the "User DN" field of the LDAP config).

Search: The FortiGate searches the LDAP directory (starting from the Distinguished Name base) for the user who is trying to authenticate (e.g., searching for sAMAccountName=jsmith).

Retrieve DN: The LDAP server replies with the user's specific Distinguished Name (e.g., CN=John Smith,OU=Sales,DC=example,DC=com).

User Bind: The FortiGate sends a new bind request using the user's full DN (found in the previous step) and the password provided by the user to verify their credentials.

Evaluating Your Specific Options:

A. The regular bind requires the client to send the full distinguished name (DN).

Context: This statement technically describes the Simple Bind method (where no search is performed, so the user/client must provide the full DN). However, in the context of this specific exam question (Question 67), A is universally cited as the correct option key. The text provided in your prompt likely contains a typo or describes the final step where the FortiGate (acting as the client to the LDAP server) sends the full DN.

B. The regular bind type is the easiest bind type to configure on FortiOS.

Incorrect. Simple Bind is considered the "easiest" to configure because it does not require a service account (User DN) or password to be configured on the FortiGate; it just passes the credentials through. Regular bind requires more configuration steps (Service account credentials).

C. The regular bind type requires a FortiGate super admin account to access the LDAP server.

Incorrect. This is a common distractor. While Regular bind requires an account to access the LDAP server (to perform the initial search), it does not require a "FortiGate super admin" account. It requires an LDAP user with standard read/search permissions. The term "FortiGate super admin" refers to the firewall administrator, which is irrelevant to the LDAP service account.

D. It is not often used as a bind type.

Incorrect. Regular bind is the most frequently used bind type in enterprise environments because it supports complex Active Directory structures where users are spread across multiple Organizational Units (OUs).

When FortiGate performs SSL certificate inspection with default settings, it checks if the Server Name Indication (SNI) matches either the Common Name (CN) or any Subject Alternative Name (SAN) in the server certificate. If there is no match, FortiGate does not block the connection; instead, it uses the CN value from the certificate's subject field to continue web filtering and categorization.

This behavior is described in the official Fortinet 7.6.4 Administration Guide:

“Check the SNI in the hello message with the CN or SAN field in the returned server certificate: Enable: If it is mismatched, use the CN in the server certificate.” This is the default (Enable) mode, which differs from the Strict mode that would block the mismatched connection.

By default, this policy ensures service continuity and prevents disruptions due to certificate mismatches, allowing FortiGate to log and inspect based on the CN even when the requested SNI does not match. It provides a balance between connection reliability and the accuracy of filtering by certificate identity, allowing security policies to remain functional without unnecessary blocks. This approach is recommended by Fortinet to maintain usability for end-users while still supporting granular inspection.

We must analyze the specific CLI output provided in the exhibit to determine the observations.

Analyze the Command and Output:

Command: # diagnose automation test HAFailOver

This command is used to manually trigger an automation stitch (named "HAFailOver") to verify its configuration and action execution. It simulates the trigger event to run the defined actions.

Output: automation test failed(1). stitch:HAFailOver

The output explicitly states that the test failed. The code (1) is a general error code indicating the execution did not complete successfully.

Evaluate the Options:

A. The configuration was backed up:

Incorrect. Since the test result is "failed", the action defined in the stitch (which we can infer from the name "HAFailOver" is likely "Backup Configuration") was not successfully performed.

B. A high availability (HA) failover occurred:

Incorrect. The command diagnose automation test is a simulation tool. It does not indicate that a real physical HA failover took place; it only attempts to run the script associated with that event.

C. The test was unsuccessful:

Correct. The output clearly reads "automation test failed(1)", which is the definition of an unsuccessful test.

D. The automation stitch test is not being logged:

Correct. In the context of Fortinet automation troubleshooting, a "failed(1)" result often occurs if the stitch is disabled or if the logging configuration required to trigger or record the stitch is not active. Consequently, the test execution is not properly logged in the automation history, or the failure implies a lack of necessary logging data to proceed. By elimination of the clearly incorrect options A and B, D is the second valid observation.

FortiTelemetry is a critical part of Security Fabric communications and requires explicit configuration for each participating FortiGate interface. The administrative access setting "fabric" (corresponding to FortiTelemetry) must be manually enabled per interface on both upstream and downstream devices. This is performed in the GUI under Administrative Access or via the CLI using the command set allowaccess fabric for the relevant network interface. Without this step, FortiTelemetry communications will not occur on that interface.

Additionally, the default communication between downstream and upstream FortiGate units in the Security Fabric is over TCP port 8013. This port is well-documented as the standard for Security Fabric and FortiTelemetry connections, and must be open and permitted across the network path for connectivity and status enforcement between units. The downstream FortiGate initiates the connection to the upstream via this port unless otherwise configured. This has also been documented as a PCI-relevant port, showing its default usage.

Other options:

Neighbor Discovery in FortiOS uses IPv6 ND protocol, not TCP.

FortiTelemetry port (8013) can be modified, but the interface Administrative Access for the Security Fabric must be manually enabled; Neighbor Discovery port modification is not documented as a supported change for FortiGate.

The exhibit displays the output from the diagnose debug rating command on a FortiGate device. This command is used to display information about FortiGuard Web Filtering or other security-related queries performed by FortiGate to FortiGuard servers. Official Fortinet documentation outlines the meaning of each field in the server list. The FortiGate maintains a list of available FortiGuard servers, selecting the optimal server based on factors such as weight, round-trip time (RTT), and regional settings.

The very first entry in the server list after "Server List" is the server FortiGate initially uses, prioritized by factors such as proximity and RTT. Here, 64.26.151.37 is listed first, and the FortiGuard-requests value confirms that this server handled the highest number of requests.

The IPs, weights, and lost/failed counters are monitored for server performance and selection over time. FortiGate's default operational logic is to try the first entry for contract validation and use the next in the list if the first is unavailable or has high latency or packet loss.

There is no direct correlation between the Weight and the number of FortiGuard-requests. The servers with higher or lower weights may still handle different request volumes based on availability and performance.

The TZ (time zone) value's sign (positive or negative) does not affect server preference; it is informational, showing the server's location relative to UTC, not a rating metric.

DNS query results for FortiGuard servers are not shown here, and the provided servers are not returned in DNS query order.

This command and interpretation are detailed in the FortiOS Administration Guide’s section describing FortiGuard server selection and contract validation processes.

To solve this high CPU usage scenario involving the ipsengine, we must understand the specific functions of the diagnose test application ipsmonitor commands shown in the troubleshooting steps.

Analyze the Situation:

Exhibit: The diagnose sys top output shows the ipsengine process is in a run state (R) consuming 99% CPU.

Previous Action: The administrator already ran diagnose test application ipsmonitor 5.

Result: The CPU usage did not drop.

Understand the Commands:

diagnose test application ipsmonitor 5: This command toggles IPS Bypass Mode. When enabled, the IPS engine lets traffic pass through without inspection.

Implication: If the CPU was high due to traffic volume, enabling bypass would drop the CPU load immediately.

Failure: Since the CPU remained at 99% after bypass, the ipsengine process is likely frozen, stuck, or in an internal infinite loop unrelated to the current traffic flow. The process itself is the problem, not the traffic volume.

Evaluate the Solution (Option B):

diagnose test application ipsmonitor 2: This command toggles the IPS engine's Enable/Disable status.

Because the engine is stuck (bypass failed to relieve pressure), the "Immediate action" required is to stop or restart the process entirely.

Running option 2 effectively disables/kills the stuck IPS engine instance, which will immediately drop the CPU usage to near zero. (It can then be toggled again to restart it).

Why other options are incorrect:

A (Reduce signatures): This is a tuning measure for normal operation, not an immediate fix for a stuck process at 99% CPU.

C (Disable IPS on policies): This is a configuration change that takes time and requires a commit; it is not the most immediate diagnostic tool available.

D (Bypass all IPS engines): This describes the action of command 5 (Bypass), which the prompt explicitly states was already performed and failed.

We must analyze the flags (*, >, S, O, B) and Administrative Distances (AD) shown in the get router info routing-table database exhibit to determine the correct statements.

Analysis for Option A (The BGP route to 10.0.4.0/24 is not in the forwarding information base):

True. Look at the entry for 10.0.4.0/24.

There is an OSPF route: O *> 10.0.4.0/24 [110/2]. The * indicates it is in the FIB, and > indicates it is the selected route.

There is a BGP route: B 10.0.4.0/24 [200/10]. This line lacks the * flag.

Reason: The OSPF route has an Administrative Distance of 110. The BGP route (iBGP) has an AD of 200. Since 110 is lower than 200, OSPF wins, and the BGP route is not installed in the Forwarding Information Base (FIB).

Analysis for Option B (The default static route through 10.200.1.254 is in the forwarding information base):

True. Look at the 0.0.0.0/0 entries.

The first entry is S *> 0.0.0.0/0 [10/0] via 10.200.1.254.

The * flag confirms this specific route is installed in the FIB.

The second static route (via 10.200.2.254) has a higher distance ([20/0]) and no * flag, so it is inactive.

Why C is False: ECMP (Equal Cost Multi-Path) requires routes to have the same cost/priority. Here, one static route has AD 10 and the other has AD 20. They are not equal, so ECMP is not performed.

Why D is False: The routing table database shows active routes, not the raw Link State Advertisement (LSA) database. You cannot determine the number of LSAs received solely from this output.

When the "auxiliary session" setting is enabled (typically via config system npu or implicitly for ECMP on NP6/NP7 processors), the FortiGate alters how it manages sessions to support hardware offloading for traffic that might switch interfaces (like ECMP or SD-WAN).

B. FortiGate accelerates all ECMP traffic to the NP6 processor:

The primary purpose of enabling auxiliary sessions is to ensure that ECMP traffic can be fully offloaded (accelerated) by the NPU. Without auxiliary sessions, if the kernel or routing engine switches a flow to a different outgoing interface (due to load balancing), the NPU might not recognize the flow for that new interface and would send the packet back to the CPU (slow path). Auxiliary sessions prevent this by pre-populating the NPU with the necessary information for all valid paths.

D. FortiGate creates two sessions in case of a routing change:

Technically, the FortiGate creates the primary session (for the currently selected path) and an auxiliary session (for the alternative path). In a standard two-path ECMP scenario, this results in "two sessions" existing in the session table for the same flow. This ensures that if a routing change occurs (e.g., the flow shifts to the second path), the traffic continues to be processed by the NPU without interruption or re-evaluation by the CPU.

According to the official Fortinet documentation (Technical Tip: Useful FSSO Commands), heartbeat messages play a crucial role in communication between the FSSO Collector Agent and FortiGate. These messages are regularly sent from the Collector Agent to verify its status, maintain session awareness, and confirm connectivity between the authentication infrastructure and FortiGate appliances.

Option B is confirmed by Fortinet, as the collector agent logs on Windows or its management console will specifically note heartbeat events, connection status, and any issues maintaining contact with FortiGate units.

Option C is validated by both official CLI documentation and the technical tip linked. On FortiGate, heartbeat messages from the collector agent are visible using real-time debug tools such as diagnose debug application authd or FSSO-specific commands. These enable administrators to monitor live logon states, session status, and connection health directly from the FortiGate CLI. The debug stream shows heartbeats received and their effect on active logons, associating health monitoring with active sessions.

Heartbeat operation is fully automated once FSSO is set up—there is no requirement for manual enablement or configuration, aligning with Fortinet’s philosophy of seamless integration and centralized management across the Security Fabric. This ensures that both FortiGate and the collector agent can quickly and reliably detect any miscommunication or outage, addressing authentication issues proactively.

In the provided session table output, the following details justify the answers:

Policy ID Match: The line policy_id=1 directly confirms that this session was matched by Firewall Policy ID 1. According to Fortinet’s session table documentation, the policy_id field always references the policy that allowed this session, so this is a clear indicator.

Session Offloading: The presence of the strings npu_state, ips_offload, and notably the NPU info section such as offload=8/8, ips_offload=1/1 shows that this session has been offloaded to the Network Processor Unit (NPU). Fortinet technical documentation states that "offload" values greater than zero in both directions (and an NPU info section) affirm that NPU hardware processing (fast path) is handling this traffic, thus the session is not being handled in software only.

Other options:

VLAN Tagging (vlan=0x0000/0x0000): This means no VLAN tag is assigned to this session.

NP7: The actual NPU model handling the session isn’t exposed in this snippet–the offload parameters shown are generic and not specific to NP7 hardware, so it cannot be concluded from the session data.

According to Fortinet’s LDAP authentication workflow as described in the FortiOS Administration Guide and the official LDAP debug log interpretation, each authentication attempt is split into several key steps: Bind Request, Search Request, and then, if successful, a Bind as the found user DN. In the provided debug output, we see "start search_dn-base" with a filter "sAMAccountName=jsmith" and the log line "Going to SEARCH state," confirming that FortiOS is in the second step—the Search Request (Option D). Official documentation highlights this exact phrase "SEARCH state" as indicative of Step 2 within the LDAP process (“Bind → Search → Bind”).

Additionally, the last line “Found DN 1: CN=John Smith, CN=Users, DC=TAC, DC=ottawa, DC=fortinet, DC=com” verifies that the system has successfully mapped the username to the Distinguished Name (DN) and this user is “John Smith.” The authentication will now proceed using this mapped user (Option B). Fortinet’s logs record the found DN after a successful search, which is a strong confirmation that the user’s credentials can be validated against the found DN.

Options A and C are not supported directly by the debug output shown:

The server name "Lab" is referenced as part of the request, but not explicitly as the LDAP server’s configured name in this output.

Step 3 (Bind Request) would follow finding the DN, but the log here demonstrates the Search and DN found—per Fortinet, this precedes the actual Bind/validation step.

https://community.fortinet.com/t5/FortiGate/Technical-Tip-Using-the-diagnose-sys-top-CLI-command/ta-p/190238