Free Practice Questions for Fortinet FCSS_NST_SE-7.6 Exam

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.

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 key point is that the two VPNs are dynamic dialup IPsec tunnels on the same interface and both are using IKEv1 main mode . In this design, FortiGate cannot reliably distinguish which dialup phase1 to match before phase 1 completes.

The uploaded Network Security Support Engineer 7.6 Study Guide shows that XAuth happens only after phase 1 is already established:

“The IKE real-time debug shows, after phase 1, the exchange of extended authentication (XAuth) packets… You can also see the CFG_REPLY, showing the XAuth user and group name.”

That means the user group is learned too late to be used for selecting the correct phase1 definition. So the fix must be applied to the phase1 matching method itself , not to XAuth.

The FortiOS administration guide gives the exact rule for this scenario:

“When the remote VPN peer has a dynamic IP address and is authenticated by a pre-shared key you must select Aggressive mode if there is more than one dialup phase 1 configuration for the interface IP address.”

The correct answers are A and D .

The debug output shows:

Sent RADIUS req to server ' RadiusServer ' : IP=172.25.188.164 ... user= " student " using CHAP

Result for radius svr ' RadiusServer ' 172.25.188.164(0) is 0

Sending result 0 for req 2

The study guide explains that in RADIUS real-time debug, FortiGate shows the IP address of the RADIUS server it is querying. In the example, it says FortiGate “creates an access request to the RADIUS server at IP address 10.0.13.130” and shows the line Sent radius req to server ... IP=10.0.13.130

So in your exhibit, the queried server is clearly 172.25.188.164 , which makes A correct.

The study guide also states:

“The message fnbamd_comm_send_result-Sending result 0 indicates that the authentication was successful and that FortiGate received the Access-Accept message.”

Since your exhibit also ends with Sending result 0 , that makes D correct.

Why the other options are wrong:

B is wrong because result 0 means authentication successful , not failed

C is wrong because the debug explicitly shows using CHAP , and the study guide lists supported RADIUS schemes as CHAP, PAP, MS-CHAP, and MS-CHAPv2

E is wrong because the study guide says two-factor authentication would involve an Access-Challenge response: “If two-factor authentication is enabled on the server, the response is an Access-Challenge message” Your exhibit shows successful result 0 / Access-Accept , not a challenge.

So the verified answers are: A, D .

Analyze the " Send to Application Layer " Message:

The most critical line in the debug output is: id=65308 ... func=av_receive ... msg= " send to application layer "

Meaning: This message indicates that the FortiGate kernel is handing the packet over to a user-space daemon (specifically the WAD/Proxy process, indicated by av_receive handlers) for deep inspection.

Implication: This behavior is the hallmark of Proxy-based inspection. In Flow-based inspection, the traffic is handled by the IPS engine (often within the kernel or via specific IPS handlers like ips_measure), and you would not typically see a " send to application layer " message for standard web filtering.

Evaluate Option B (Firewall Policy Mode):

Since the traffic is being sent to the application layer proxy, the Firewall Policy controlling this traffic (Policy ID 1, as seen in Allowed by Policy-1) must be configured with Inspection Mode = Proxy. If it were Flow-based, the traffic would stay in the flow path. Thus, Option B is correct.

Evaluate Option C (Web Filter Profile Mode):

In FortiOS, when a firewall policy is set to Proxy-based inspection, the security profiles (like Web Filter) applied to that policy also operate in Proxy-based inspection mode. The presence of the av_receive function confirms that the content inspection (Web Filter/AV) is being performed by the proxy engine. Thus, Option C is correct.

Why Option A is Incorrect (NPU Offload):

The output shows npu_state=0x100. In the context of a flow trace where traffic is being " sent to application layer, " this confirms the session is not fully offloaded to the NPU (Network Processor). Offloaded traffic (Fast Path) is handled by the hardware and would not generate these specific CPU-level debug logs for the payload inspection phase. The proxying process requires CPU intervention.

Why Option D is Incorrect (Port Mapping):

While valid protocol mapping is necessary for inspection, the specific debug output shown is a direct result of the Inspection Mode (Proxy vs. Flow). The observation of the traffic moving to the application layer is primarily caused by the policy and profile mode settings, making B and C the direct " observations " derived from the log data.

The 8.8.8.8/32 route is visible in the OSPF database on FGT-B but not installed into the routing table—the most likely explanation is that FGT-B is filtering it from being installed.