Fortinet FCSS_NST_SE-7.6 Dumps

The BGP debug output shows session information for peers, including state details. According to official Fortinet BGP documentation, if the session state with a peer does not show " Idle, " " Active, " or " Connect, " but instead shows " Established, " " Up, " or related counters (e.g., messages sent/received or uptime), it indicates the session is operational. In this scenario, the peer 10.127.0.75 is the only one showing a positive indication of a live, established session. Other options like neighbor-range configuration, AS mismatch, or route-maps blocking prefixes are not supported by evidence provided in a simple BGP session state debug, nor does the output show errors relating to local or remote AS issues.

The correct interpretation comes from Fortinet ' s BGP troubleshooting guide, which outlines how to read session status and neighbor states in debug and summary outputs.

The correct answer is B .

The study guide explicitly states that slabs are used by the kernel : “The kernel memory slabs are collections of objects with a common purpose. The kernel uses them to store information in memory.”

It also gives the exact calculation method: “Total slab size = available objects x object size” and explains that in the diagnose hardware sysinfo slab output, the columns are active objects , available objects , and object size

From the exhibit:

tcp_session 3 5 1500 ...

available objects = 5

object size = 1500

So:

Total slab size = 5 × 1500 = 7500

That matches option B .

Why the other options are wrong:

A : ip_session 10 10 1408 ... gives 10 × 1408 = 14080 , but slabs are associated with the kernel , not user space

C : ip6_session 5 0 1472 ... gives 0 × 1472 = 0 , not 1472

D : UDPv6 15 10 1408 ... gives 10 × 1408 = 14080 , but again slabs are associated with the kernel , not user space

So the verified answer is B .

The correct answers are A and B .

The Network Security Support Engineer 7.6 Study Guide states under OSPF Troubleshooting :

“Follow these steps to troubleshoot an OSPF problem between two peers:

Check that the local router can reach the remote peer. IP addresses must be in the same subnet and have the same subnet mask.

Ensure that IP protocol 89 is not blocked.

Hello and dead intervals must match.

The OSPF router ID for each peer must be unique. Duplicate router IDs are not allowed.

Do the MTUs match?

If authentication is enabled, the type and password must match on both sides.”**

The same page also summarizes the troubleshooting tips as:

“Do peers have an IP address within the same subnet?”

“Is IP protocol 89 blocked?”

This directly confirms:

A is correct

B is correct

Why the other options are wrong:

C is wrong because TCP port 179 is used by BGP , not OSPF. OSPF uses IP protocol 89 , as the study guide explicitly notes

D is wrong because the study guide’s OSPF adjacency troubleshooting checklist does not require an active static route to the peer. OSPF neighbors form adjacency on directly reachable networks, and the guide instead focuses on same subnet, protocol 89, intervals, router ID, MTU, and authentication matching

So the verified answers are: A, B .

The correct answers are A and B .

The exhibit shows:

override: disable

both members are currently in-sync

only port7 appears under HBDEV stats , so it is the active heartbeat interface

the cluster is in HA A-P mode

Why A is correct:

With override disabled , after a failover the new primary keeps that role when the old primary comes back. The FortiOS administration guide states:

“When the primary FortiGate rejoins the cluster the secondary FortiGate continues to operate as the primary FortiGate.”

So if FGVM...649 reboots and FGVM...650 becomes primary, FGVM...650 will remain primary after FGVM...649 rejoins.

Why B is correct:

The study guide states:

“When FortiGate devices configured in an HA cluster lose communication with each other on the heartbeat interface, each FortiGate assumes the role of the primary device.”

The exhibit shows only port7 as the heartbeat device in HBDEV stats

So if port7 is disconnected and heartbeat communication is lost, the cluster can enter a split-brain condition, where both units believe they are primary. The FortiOS administration guide confirms the same behavior: loss of heartbeat communication causes each member to think it is the primary

Why the other options are wrong:

C is wrong because configuration synchronization status is specifically used to detect whether secondary members remain synchronized with the primary. If members are no longer synchronized, the status changes from in-sync to out-of-sync

D is wrong because the study guide explains that during a configuration change, checksums may differ briefly while changes are copied, but it does not describe this as the secondary initiating a “synchronization reset”

So the verified answers are: A, B .

The best verified answer is C .

The study guide says that when FortiGate is in conserve mode, it activates protection measures to recover memory space:

“System configuration cannot be changed”

“FortiGate skips quarantine actions (including FortiSandbox analysis)”

It also explains that inspection behavior can be reduced while in conserve mode:

“pass (default): All new sessions pass without inspection until FortiGate switches back to non-conserve mode.”

“The av-failopen setting also applies to flow-based antivirus inspection.”

The FortiOS administration guide summarizes this behavior as:

“This causes functions such as antivirus scanning to change how they operate to reduce the functionality and conserve memory without compromising security.”

That is why C is the closest correct choice: FortiGate can reduce functionality of some processes, especially antivirus-related inspection, to preserve memory.

Why the other options are wrong:

A is wrong because FortiGate does not automatically reboot as a default conserve-mode action. A reboot can be configured through an automation stitch , but that is an optional administrator-defined response, not the built-in conserve-mode behavior

B is wrong because the documentation does not say FortiGate switches from proxy-based inspection to flow-based inspection. Instead, it may pass traffic without inspection depending on av-failopen settings

D is not generally correct for conserve mode . The study guide says FortiGate starts dropping new sessions only when memory usage exceeds the extreme threshold : “If memory usage exceeds the extreme threshold, all new sessions that require inspection (flow-based or proxy-based) are blocked.”

So the verified answer is: C .

The reported symptom—users unable to access any websites despite no explicit blocks in the profile—points to systemic connectivity or configuration issues rather than specific URL filtering rules.

Option B (SSL/TLS Inspection): When Deep Inspection is enabled, the FortiGate acts as a Man-in-the-Middle (MitM) and re-signs server certificates using its own CA. If the clients (browsers) do not trust this CA (i.e., the certificate is not installed in their Trusted Root store), they will reject the connection with certificate errors, effectively preventing access to all HTTPS websites.

Option D (DNS): Web browsing relies on DNS resolution . If the configured DNS server is unreachable or failing, the FortiGate (or the client) cannot resolve FQDNs to IP addresses. Consequently, browsers will fail to load any page, resulting in a total loss of web access.

Option E (License): If the FortiGuard Web Filtering license expires, the FortiGate can no longer query the FortiGuard Distribution Network (FDN) for ratings. By default, or if the allow-when-rating-error setting is disabled (a common security practice), the FortiGate will block all web traffic that it cannot rate, often displaying a " Web Filter Service Error " or invalid license page.

Option A is incorrect because clearing the cache only increases latency, it does not block traffic. Option C is incorrect because webfilter-force-off is typically used to disable the service (often allowing traffic to bypass checks if the service is down), rather than blocking it.

The correct answers are A and D .

The Network Security Support Engineer 7.6 Study Guide explains that automation stitches consist of a trigger and one or more actions , and that they can detect events such as high CPU and conserve mode across the Security Fabric

The FortiOS administration guide then gives the exact practical example for A :

“Automation stitches can be created to run a CLI script and send an email message when memory or CPU usage exceeds specified thresholds.”

It also shows examples where the email body contains the script output using:

%%results%%

That directly confirms A .

For D , the FortiOS administration guide states:

“The URI and HTTP body can use parameters from logs or previous action results.”

It also explains the execution model:

“The stitch Action execution can be set to either Sequential or Parallel. In sequential execution actions will execute one after another with a delay (if specified). … In parallel execution all actions will execute immediately when the stitch is triggered.”

A concrete example shows a second action using the output of the first action:

“This string for the body text includes the results from the preceding CLI script action.” with

Body=%%results%%...

That confirms D .

Why the other options are wrong:

B is wrong because automation stitches can be triggered by IPS events, but the documentation does not describe them as modifying packet headers or payloads. Instead, they perform actions such as email, CLI script, webhook, quarantine, and similar automated responses

C is wrong because delay is associated with sequential execution, not parallel execution. The guide explicitly says: “A delay can be added before an action if Sequential action execution is used.”

So the verified answers are: A, D .

The correct answers are A and B .

The study guide says:

“If NAT-T is enabled, and there is a FortiGate located in the middle that is running NAT, the sniffer command must use a different filter. In this case, IKE traffic uses UDP port 500, but switches to UDP port 4500 during the tunnel negotiation. Additionally, ESP traffic is encapsulated inside the UDP 4500 channel.”

It also says:

“In some networks, UDP is blocked by firewalls or ISPs. In those cases, you can configure your VPN tunnel to use IKE over TCP in the phase 1 configuration. The default IKE TCP port is 443…”

And the study guide gives the correct capture examples:

No NAT: host < remote-gw > and udp port 500

With NAT and NAT-T: host < remote-gw > and (udp port 500 or udp port 4500)

So:

B is correct because with NAT Traversal enabled , the tunnel may no longer be using only UDP 500 . It can move to UDP 4500 , so the current filter may miss the traffic.

A is correct because the filter may need to be expanded to include UDP 4500 for NAT-T, or TCP 443 when IKE over TCP is used.

Why the other options are wrong:

C is wrong because restricting the filter to the remote peer IP can make the capture more precise, but it is not required for the sniffer to display output. The problem here is the port/protocol choice , not the lack of a host filter. The study guide examples use host filtering as an aid, not as a requirement.

D is wrong because diagnose debug enable is used to enable real-time debug output for applications, but it does not suppress or invalidate sniffer output . Sniffer capture is a separate command path. Fortinet documentation separately documents diagnose sniffer packet ... for packet capture and diagnose debug enable for debug features.

So the verified answers are: A, B .

The correct answer is A . This behavior is dictated by the configuration command set snat-route-change enable shown in Exhibit 1 under config system global.

Routing Change: By changing the priority of route ID 2 from 10 to 0, it becomes lower than route ID 1 (priority 5). In FortiOS, a lower priority value indicates a more preferred route. Consequently, the active route for the destination changes from port1 to port2 .

SNAT Implication: The existing session (shown in Exhibit 2) is using Source NAT (SNAT) with the IP address associated with port1 (10.200.1.1). If the traffic were simply switched to port2 , the source IP would be incorrect for that interface and the return traffic would likely fail or be dropped.

snat-route-change enable: This specific setting instructs the FortiGate on how to handle established SNAT sessions when a routing change occurs that alters the preferred outgoing interface. When enabled, if a route change forces an SNAT session to a new interface, FortiGate flushes (deletes) the session from the session table. This is necessary because a live TCP session cannot survive a change in its source IP address. The client must initiate a new session, which will then be created using the new correct route (port2) and the corresponding new SNAT IP.

If this setting were disabled, the session would likely remain " sticky " to the original interface (port1) until it closed, provided the route still existed. However, the explicit configuration forces the deletion.

According to the official Fortinet administration guide for FortiOS 7.6.4 under the section " Configuring a RADIUS server, " the supported RADIUS authentication methods you can configure via the CLI with config user radius are:

pap

chap

mschap

mschapv2

auto

The relevant CLI syntax is set auth-type {auto | ms_chap_v2 | ms_chap | chap | pap}​. You can confirm this directly in the configuration table and from real CLI sessions.

EAP (Extensible Authentication Protocol) is NOT an authentication option you can directly set under config user radius. EAP methods (such as EAP-TLS, EAP-PEAP, EAP-TTLS) are negotiated between the RADIUS client and server but are not configurable as an explicit auth-type option in FortiOS. EAP authentication is typically used automatically by features like 802.1X, not through the user radius object authentication-type setting, and always requires proper backend workings between supplicant and RADIUS server

The 7.6 study guide explains the route selection order:

“Route Selection Process

Most specific route

Lowest distance

Lowest metric (dynamic routes)

Lowest priority (static routes)

ECMP (static, BGP, and OSPF routes)”**

It then states:

“If there are multiple routes with the same netmask, distance, metric, and priority, FortiGate shares the traffic among all of them. This is called equal-cost multi-path (ECMP).”

The FortiOS administration guide confirms the ECMP prerequisite:

“Routes must have the same destination and costs. In the case of static routes costs include distance and priority.”

In the exhibit, the kernel/FIB output shows the two default routes as:

gwy=100.64.1.254 dev=3 (port1) prio=0

gwy=100.64.2.254 dev=6 (port2) prio=10

So although both are default routes, their priorities are different . Since FortiGate uses the FIB/kernel for forwarding traffic, ECMP will not happen until the static-route priorities are the same. The study guide also notes that the FIB is the table used to perform standard routing

Therefore, to make the two default routes eligible for ECMP, the administrator must make the priorities equal. Since port2 is already 10, the needed change is to set the port1 default route priority to 10.

Why the other options are wrong:

A is wrong because snat-route-change affects how existing SNAT sessions react to routing changes, not whether static routes qualify for ECMP

B is wrong because changing port2 to priority 1 still would not match port1 at 0, so the routes still would not have equal cost for ECMP

C is wrong because preserve-session-route affects existing-session route persistence after routing changes, not ECMP qualification

To display debug output on FortiGate devices, you must always run both the application-specific debug command and the global debug enable command. The command diagnose debug application ike -1 sets up the detail level for the IKE daemon debug, but it does not display any debug output on its own. As described in the FortiOS CLI debugging manuals, the command diagnose debug enable activates debug output on the console, making all previously set debugs visible. This is especially important for VPN troubleshooting—without the enable command, no output appears even if there is VPN traffic.

The correct diagnostic sequence is:

diagnose debug application ike -1

diagnose debug enable

This procedure is found in every FortiOS CLI debug tutorial and troubleshooting workflow.

The exhibit shows:

memory conserve mode: on

memory used: 2706 MB 89% of total RAM

memory used threshold red: 2675 MB 88% of total RAM

memory used + freeable threshold extreme: 2887 MB 95% of total RAM

The study guide states that the default thresholds are:

Extreme = 95%

Red = 88%

Green = 82%

So this FortiGate is in conserve mode because memory usage is 89% , which is above the red threshold (88%) , but it has not yet reached the extreme threshold (95%) .

The study guide then explains exactly what happens during conserve mode:

“For traffic that requires proxy-based inspection (and if memory usage has not exceeded the extreme threshold):

config system global

set av-failopen [off | pass | one-shot]

pass (default): All new sessions pass without inspection”

It also says:

“The av-failopen setting also applies to flow-based antivirus inspection.”

And the same page adds:

“If memory usage exceeds the extreme threshold, all new sessions that require inspection (flow-based or proxy-based) are blocked.”

Therefore, with default settings and with memory usage below the extreme threshold , FortiGate is allowing new sessions that require inspection, but bypassing inspection . That matches C .

Why the other options are wrong:

A is wrong because the default behavior is not to block proxy-based inspected sessions; the default is pass , meaning they pass without inspection

B is wrong because if memory rises another 6% , it reaches 95% , which is the extreme threshold . At that point, the study guide says all new sessions that require inspection are blocked

D is wrong because FortiGate blocks all new inspected sessions only when memory usage exceeds the extreme threshold , and the exhibit shows it is currently at 89% , not 95%

To determine the correct conclusions, we analyze the specific lines in the IKE real-time debug output provided in the exhibit:

Analysis for Option A (The remote peer is the initiating peer):

Evidence: The very first line of the debug output reads: ike 0:624000:98: responder: main mode get 1st message...

The keyword responder indicates that this local FortiGate is receiving the connection request. Consequently, the remote peer must be the initiator sending the request. The phrase " get 1st message " confirms the local unit is receiving the initial packet of the negotiation sequence.

Conclusion: This statement is True.

Analysis for Option B (This is a phase 1 negotiation):

Evidence: The same line mentions main mode.

In IPsec VPNs, Main Mode and Aggressive Mode are exclusively used for Phase 1 (IKE SA) negotiations. Phase 2 (Child SA) negotiations use Quick Mode. The presence of " main mode " definitively identifies this as a Phase 1 exchange.

Conclusion: This statement is True.

Analysis for Option C (There is a Diffie-Hellman group mismatch):

Evidence:

Incoming proposal (Remote): Lists type=OAKLEY_GROUP, val=MODP2048 (Group 14) in the first proposal proposal.

My proposal (Local): Lists type=OAKLEY_GROUP, val=MODP2048 (Group 14).

Since both the remote peer and the local gateway support and are proposing MODP2048 (Group 14), there is no Diffie-Hellman group mismatch. The actual mismatch visible in the logs is between the Encryption/Hash algorithms (Remote proposes AES-256/SHA2-256, while Local proposes AES-128/SHA), but the DH groups match.

Conclusion: This statement is False.

Analysis for Option D (This is a phase 2 negotiation):

As established in the analysis for Option B, " Main Mode " is a Phase 1 protocol. If this were Phase 2, the debug would show " Quick Mode " .

Conclusion: This statement is False.

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.

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.

To determine the path the traffic will take, we must look at the FortiGate Route Lookup Precedence (Packet Processing Flow) and the specific configurations shown in the exhibit

Analyze the Routing Precedence:

In FortiOS, when a packet arrives (and is not part of an existing session), the FortiGate performs route lookups in a specific order:

Policy Routes: Configured under config router policy (or diagnose firewall proute list). These are checked first. If a packet matches the criteria (Source, Destination, Protocol, Incoming Interface), the Policy Route is used immediately, bypassing the standard routing table.

FIB (Forwarding Information Base): If no Policy Route matches, the device looks at the standard routing table (Static, Connected, Dynamic).

Analyze the Exhibit:

Policy Route Section: The output of diagnose firewall proute list shows an active policy route (id=1).

Destination: 100.65.0.0/255.255.255.0 (Matches the network in the question).

Action: It directs traffic to gateway 10.0.4.253 via oif=6(port4).

Routing Table Section: The output of get router info routing-table database shows multiple routes for 100.65.0.0/24 (Static, OSPF, BGP) all with distance 10. The Static route (S) is currently selected (* > ) in the FIB.

Conclusion:

Because Policy Routes take precedence over the standard routing table (FIB), the FortiGate will forward the traffic using the instructions in Policy Route ID 1. It will not use the Static, BGP, or OSPF routes visible in the routing table for any traffic that matches the policy route ' s criteria (ingress port 3).

The correct answer is D .

The study guide shows the ipsmonitor test usage exactly:

1: Display IPS engine information

2: Toggle IPS engine enable/disable status

5: Toggle bypass status

99: Restart all IPS engines and monitor

So diagnose test application ipsmonitor 5 is used to toggle bypass status , which corresponds to enabling IPS bypass mode .

Why the other options are wrong:

A is wrong because disabling the IPS engine is option 2 , not 5.

B is wrong because the study guide does not define option 5 as IPS session information.

C is wrong because restarting all IPS engines and monitors is option 99 , not 5.

So the verified answer is: D .

The output of the diagnose sys session list command provides the critical evidence needed to determine the behavior during a failover:

Session Synchronization (synced):

The most important indicator in the exhibit is the synced flag located in the state= line (state=may_dirty synced none app_ntf).

In FortiOS HA (High Availability), the synced flag confirms that this specific session has been successfully synchronized from the primary device to the secondary (backup) device.

Session synchronization (Session Pickup) ensures that if the primary unit fails, the secondary unit already has the session in its table and can resume traffic processing immediately.

TCP State (proto_state=01):

The output shows proto=6 (TCP) and proto_state=01.

In the FortiGate session table, proto_state=01 for TCP indicates that the session is in the ESTABLISHED state (post-three-way handshake).

This invalidates Option B, which claims the TCP session is not fully established.

Failover Outcome:

Because the session is ESTABLISHED and SYNCED, the secondary device will seamlessly take over the session upon primary failure.

The traffic continues to flow through the new primary without requiring the user/client to restart the connection. This is the primary function of HA Session Pickup.

Why other options are incorrect:

A: While the output shows app_ntf (Application Control notification) and may_dirty, the presence of the synced flag overrides this concern regarding failover. If the session type were not supported for failover (e.g., certain proxy sessions in older versions), it would not be marked as synced. Since it is synced, it persists.

B: As noted, proto_state=01 means established, not " not fully established " .

D: While the kernel updates routing tables, the purpose of syncing the session is to preserve the state so it does not need to be re-evaluated as a new packet would, preventing traffic drops.

The correct answers are A and D .

The study guide states:

“Application layer test commands do not display information in real time. They display statistics and configuration information about a feature or process. You can also use some of these commands to restart a process or execute a change in its operation.”

This directly proves:

A is correct because they can display statistics and configuration information

D is correct because some of them can restart a process/application

Why the other options are wrong:

B is wrong because the study guide explicitly says application-layer test commands do not display information in real time . Real-time output is done with diagnose debug application ... commands instead.

C is wrong because diagnose debug console enable is related to debug output behavior, not a requirement for application-layer test commands to display output. The study guide does not describe test commands that way.

====

The get router info bgp summary output lists BGP neighbor status:

Prefix Reception: The " State/PfxRcd " column shows the number of prefixes received from the neighbor—neighbor 100.64.1.254 has " 1 " , confirming option A.

Received Message Count: Under " MsgRcvd " , 18 packets have been received from neighbor 100.64.1.254. This matches option C.

The second neighbor 100.64.2.254 is in " Active " state and has received/sent 0 packets, indicating that its TCP connection is NOT established, disproving option B.

There is no indication anywhere that the router is " still calculating " prefixes; " Active " just means no session is established, so option D is incorrect.

The Network Security Support Engineer 7.6 Study Guide explicitly explains this debug message:

“iprope_in_check() check failed, drop” means the packet is destined to a FortiGate IP address and one of these conditions applies:

The service is not enabled

The service is using a different TCP port

The source IP address is not included in the trusted host list

The packet matches a local-in policy with action deny

That directly confirms C. Trusted host list misconfiguration .

Why D is the second valid choice:

The FortiOS administration guide explains that:

“IP pools and VIPs are considered local IP addresses if responding to ARP requests on these external IP addresses is enabled … the FortiGate is considered a destination for those IP addresses … once an IP pool or VIP has been configured … the FortiGate considers it as a local address and will not forward traffic based on the routing table.”

Because iprope_in_check() is a local-in/local-destination type failure, a VIP or IP pool misconfiguration can cause traffic to be treated as destined for the FortiGate itself, which can then trigger this drop condition if the matching local service/local-in handling is not valid. So D is the closest supported second answer from the available choices.

Why the other options are wrong:

A is wrong because policy route problems are not the documented meaning of this specific debug message. The study guide instead ties iprope_in_check() check failed, drop to management/local-in conditions.

B is wrong because the study guide says traffic shaping drops appear as: “Denied by quota check”

The Internet Key Exchange version 2 (IKEv2) protocol simplifies the negotiation process compared to IKEv1. It is defined by a specific sequence of message exchanges to establish a secure IPsec tunnel.

The correct chronological order of the IKEv2 exchanges is:

IKE_SA_INIT (Initial Exchange):

This is the first exchange. It negotiates the security parameters for the IKE Security Association (IKE SA), sends nonces, and performs the Diffie-Hellman key exchange. At the end of this exchange, the communication is encrypted, but the peers are not yet authenticated.

IKE_AUTH (Authentication Exchange):

This is the second exchange. It authenticates the previous messages, exchanges identities and certificates (if used), and establishes the first Child SA (the actual IPsec Security Association used for data traffic).

CREATE_CHILD_SA (Subsequent Exchanges):

This exchange occurs after the IKE SA and the initial Child SA are established. It is used to create additional Child SAs (for different traffic selectors) or to perform re-keying for the IKE SA or existing Child SAs.

Why other options are incorrect:

A & B: Incorrect because CREATE_CHILD_SA cannot happen before the SA is initialized (IKE_SA_INIT) and authenticated (IKE_AUTH).

D: Incorrect because IKE_AUTH cannot occur before IKE_SA_INIT.

Therefore, the protocol flow is IKE_SA_INIT $\rightarrow$ IKE_AUTH $\rightarrow$ CREATE_CHILD_SA.

Comprehensive and Detailed Explanation From Exact Extract of Network Security Support Engineer Study Guide (FortiOS 7.6) topics:

The correct answers are A and B . Security Fabric communication uses Fortinet-proprietary protocols, mainly FortiTelemetry and Neighbor Discovery . The study guide states that FortiTelemetry uses TCP port 8013 , and that the connection is always established by the downstream FortiGate toward the upstream FortiGate . This validates option A . The same section also states that FortiTelemetry must be manually enabled . More precisely, the upstream FortiGate interface must have Security Fabric Connection enabled under administrative access so it can accept incoming Security Fabric connection requests. This validates option B .

Option C is wrong because only the FortiTelemetry TCP port 8013 can be changed; Neighbor Discovery uses UDP port 8014 and cannot be changed. Option D is also wrong because Security Fabric communication is not enabled automatically among all Fortinet devices. It requires the correct Security Fabric settings, interface administrative access, and downstream authorization. The study guide’s troubleshooting section confirms that when FortiTelemetry is disabled, the upstream FortiGate receives TCP 8013 SYN packets but does not complete the Security Fabric connection.

From the exhibit, you can observe that the debug output captures an IKEv1 negotiation in aggressive mode. Let ' s break down the supporting details in line with official Fortinet IPsec VPN troubleshooting resources and debug guides:

For Option B:

The very first line of the debug output shows:

comes 10.0.0.2:500- > 10.0.0.1:500, ifindex=7.

This indicates the traffic direction—from the remote IP (10.0.0.2) with port 500 to the local IP (10.0.0.1) with port 500. According to Fortinet ' s documentation, the right side of the arrow always represents the local FortiGate gateway. Thus, 10.0.0.1 is the local gateway IP address.

For Option D:

You see the statement:

negotiation result " remote "

and

received peer identifier FQDNCE88525E7DE7F00D6C2D3C00000000

Official debug documentation describes that the " peer identifier " or peer ID sent by the initiator is displayed here. In the context of IKE/IPsec negotiation, this value is used as the IPsec peer ID for authentication and identification purposes. The initiator is providing " remote " as the peer ID for its connection.

Why Not A or C:

Perfect Forward Secrecy (PFS): The debug does not show any DH group negotiation in phase 2 (no reference to group2, group5, etc., for phase 2), so you cannot deduce the presence of PFS solely from this output.

Phase 2 negotiation: The log focuses on IKE (phase 1) negotiation and establishment; there’s no reference to ESP protocol, Quick Mode, or other identifiers that would show phase 2 SA negotiation and establishment.

This interpretation aligns with the explanation in the FortiOS 7.6.4 Administration Guide ' s VPN section and the official debug command output samples published in Fortinet’s documentation. It demonstrates how to distinguish between local and remote addresses and how to identify the use of peer IDs.

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.

The correct answer is D. The inbound IPsec SA was copied to the NPU.

The exhibit shows:

npu_flag=02

dec_npuid=1

enc_npuid=0

The study guide gives the exact meaning of the npu_flag field:

npu_flag=00 = Both IPsec SAs loaded to the kernel

npu_flag=01 = Outbound IPsec SA copied to NPU

npu_flag=02 = Inbound IPsec SA copied to NPU

npu_flag=03 = Both outbound and inbound IPsec SAs copied to NPU

It also explains: “If the first IPsec packet is inbound and can be offloaded, the inbound SA is copied to the NPU and the npu_flag changes to 02. After both SAs are copied to the NPU, the npu_flag changes to 03.”

So with npu_flag=02, only the inbound SA has been copied to the NPU. That makes D correct.

Why the other options are wrong:

A is wrong because outbound-only offload would be npu_flag=01, not 02

C is wrong because both directions offloaded would be npu_flag=03, not 02

B is wrong because dec_npuid=1 identifies the NPU ID used for decryption, but it does not state that the processor is specifically NP6 . The study guide only maps the offload state through the npu_flag values in this context, not the NPU model from this field alone

So the verified answer is: D .

To determine the cause of the failure, we must analyze the IKEv2 debug output provided in the exhibit (image_ad3dc6.jpg):

Identify the Negotiation Phase:

The debug log shows: responder received CREATE_CHILD exchange.

In IKEv2, the CREATE_CHILD_SA exchange is used to create new Child SAs (Phase 2) or to rekey existing ones.

The fact that the tunnel was previously " brought up successfully " implies the initial IKE SA (Phase 1) is stable, and this error is occurring specifically during a rekey event, which often involves Perfect Forward Secrecy (PFS).

Analyze the Proposals (The Mismatch):

Incoming Proposal (Remote Peer):

The remote peer sends a proposal containing two Diffie-Hellman groups: type=DH_GROUP, val=MODP2048 (Group 14) and type=DH_GROUP, val=MODP1536 (Group 5).

My Proposal (Local FortiGate):

The local FortiGate configuration expects: type=DH_GROUP, val=MODP3072 (Group 15).

Result of the Negotiation:

The debug output concludes with: no proposal chosen and Negotiate SA Error.

This error occurs because the local FortiGate cannot find a common Diffie-Hellman group between what it requires (Group 15) and what the peer is offering (Groups 14 or 5).

While this is technically a mismatch occurring during the Phase 2 (Child SA) creation, " A Diffie-Hellman mismatch " (Option A) is the precise root cause identified in the logs.

Why other options are incorrect:

B: The log shows received create-child request, confirming that UDP traffic is reaching the device and is not blocked.

C: The failure is in the CREATE_CHILD exchange (Phase 2/Rekey), not the IKE_SA_INIT or IKE_AUTH (Phase 1) exchanges.

D: While the mismatch is occurring within the Phase 2 definitions, Option A is the specific technical reason for the no proposal chosen error shown in the DH_GROUP lines.

The correct answers are C and D .

The key clue is the command itself:

diagnose debug application fssod -1

The study guide explicitly states: “There is a specific FortiGate daemon that handles the polling mode. It is the fssod daemon. To enable agentless polling mode real-time debug use the command: diagnose debug application fssod -1.”

That directly proves D. FSSO is using agentless polling mode to detect logon events .

The study guide also states: “In agentless polling mode, FortiGate frequently polls all workstations (as a standalone collector agent does) to check which users are still logged in. You can sniffer this traffic on port 445.”

That directly proves C. FortiGate is frequently polling the workstation in case the user has logged out .

Why the other options are wrong:

A is wrong because the “cannot verify if the user is still logged in” / Not Verified condition is described for the collector agent workstation status, not as a conclusion from this FortiGate fssod debug line. The study guide says: “A user goes to not verified status when they log out, or when there is a problem in the polling done by the collector agent to the workstation.”

B is wrong because DC Agent mode is part of agent-based FSSO , where DC agents send events to a collector agent. This output is from the fssod daemon, which the study guide ties to agentless polling mode , not DC Agent mode.

E is wrong because TCP port 8000 is used for communication between the collector agent and FortiGate , while in agentless polling mode FortiGate polls workstations and that traffic can be sniffed on TCP port 445 .

So the verified answers are: C, D .