NSE7_FSN_AR-7.6 Exam Dumps - Fortinet NSE 7 - Secure Networking 7.6 Architect

The correct answer is D. IKE_AUTH.

The study guide explicitly states:

“IKE_Auth exchange:

• Performs the mutual authentication of two IKE endpoints.

• Configures settings like IP/mask, DNS, and so on.

• Sets up the piggyback of a child SA. Negotiates IP flow and security settings for the IPsec SA.”

It also says:

“By default, a piggyback child (IPsec) SA is negotiated along with the IKEv2 SA during IKE_AUTH. If additional IPsec SAs are needed … they are negotiated during subsequent CREATE_CHILD_SA exchanges.”

Why the other options are wrong:

A. IKE_SA_INIT is incorrect because this exchange negotiates the security settings to protect the IKE traffic, not the first CHILD_SA.

B. INFORMATIONAL is incorrect because it is used to convey control messages between IKE endpoints.

C. CREATE_CHILD_SA is incorrect for the first CHILD_SA, because it is used to create new additional child SAs or rekey existing ones after the initial exchange.

The study guide identifies this exact output as an expectation session created by the FTP session helper:

“run helper-ftp” indicates the FTP helper is in use.

“FortiGate created an expectation session and opened the pinhole port for the expected return traffic”

It also explains why this exists:

“Another important function of the session helper is to temporarily create an expected session (or pinhole) for the data channel connection that comes from the server.”

“The session helper automatically creates the session and opens the door for the incoming connection.”

“These incoming TCP sessions use random TCP port numbers.”

That directly proves C is correct.

For A, the exhibit shows expire=23. The study guide explains the expire field as the length of time until the session expires if no matching traffic arrives, and the FortiOS guide states for expectation sessions:

“Expectation sessions usually have a timeout value of 30 seconds. If the communication from the server is not initiated within 30 seconds the expectation session times out and traffic will be denied.”

So with expire=23, FortiGate will allow that expected traffic only for the remaining 23 seconds; after that, it times out and the traffic is denied. That makes A correct.

Why the other options are wrong:

B is not supported. The study guide describes expectation sessions as being created by the session helper from the control-session negotiation, not as independent objects unaffected by the master session.

D is wrong as stated. Even though the output contains policy_id=25, the study guide explicitly says the incoming expected connection is allowed by the expected session itself, “even when no firewall policy allows it.”

To identify the reason for the lack of prefixes, we must interpret the State/PfxRcd and Up/Down columns in the get router info bgp summary exhibit.

Analyze Neighbor Status:

Neighbor 10.125.0.60: State is OpenSent. This session is not established. It is stuck in the negotiation phase.

Neighbor 100.64.3.1: State is Active. This session is not established. The router is actively trying to initiate a TCP connection.

Neighbor 10.127.0.75:

Up/Down: 02:45:55. This indicates the BGP session has been Up (Established) for almost 3 hours.

State/PfxRcd: 0. This number represents the count of prefixes received. The session is fully established, but the neighbor has sent zero routes.

Determine the Cause:

Since the session with 10.127.0.75 is established, connectivity and handshakes (Options A, B, C) are not the issue for this neighbor.

The fact that it is Up but sending 0 prefixes strongly implies that the neighbor is configured to filter out its routes before sending them to the local FortiGate.

Option D correctly identifies this as a RIB-OUT (Routing Information Base - Outbound) configuration issue on the neighbor (Router 10.127.0.75), which prevents it from advertising its routes.

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.

The correct answers are A and C.

The study guide describes this exact asymmetric ICMP scenario. It states:

“The server sends an echo request to the PC through port2 of the local router, effectively bypassing FortiGate. When it receives the echo request, the PC responds with an echo reply through its default gateway, 10.1.0.2, which is port1 on FortiGate. Because there is no existing session, the echo reply is dropped. All subsequent echo replies are blocked.”

That means the current problem exists because:

the ICMP request bypasses FortiGate

the ICMP reply goes through FortiGate

FortiGate has no matching session, so it drops the reply

The study guide then shows the exact corrective option:

“Allowing asymmetric routing:”

config system settings

set asymroute enable

end

It further explains:

“After the packet passes through the FortiGate CPU, FortiGate forwards the packet using the FIB, even though there are no session matches. FortiGate forwards all subsequent echo replies using the FIB.”

So A is correct.

The other valid fix is to make the traffic symmetric by changing the laptop’s default gateway so the reply no longer goes through FortiGate. In the exhibit, the alternate gateway is 10.1.0.254, which is the local router on the same subnet. If the laptop uses 10.1.0.254 instead of 10.1.0.2, the ICMP echo reply follows the same bypass path as the echo request, so the server receives it without involving FortiGate session validation. This makes C correct.

Why the other options are wrong:

B is wrong because this is not an RPF problem. The study guide explains RPF as a reverse path lookup used to validate whether a packet arrived on a legitimate interface, mainly for spoofing protection. The issue in this scenario is a missing session due to asymmetric routing, not a strict-versus-feasible RPF failure

D is wrong because FortiGate already has the specific route 10.4.0.0/24 through port3 in the routing table shown in the exhibit, so adding a default static route to port3 is unnecessary and not the reason the echo reply is being dropped

So the verified answers are: A, C.

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 correct answer is B.

In the exhibit:

Neighbor 100.64.1.254 shows State/PfxRcd = 1, which means the session is established and the local FortiGate has received 1 prefix

Neighbor 100.64.2.254 shows State/PfxRcd = Active

The study guide explains the BGP states exactly:

Connect: Waiting for a successful three-way TCP connection

Active: Unable to establish the TCP session

OpenSent: Waiting for an OPEN message from the peer

OpenConfirm: Waiting for the keepalive message from the peer

Established: Peers have successfully exchanged OPEN and keepalive messages

It also explains how to read the State/PfxRcd column:

“If the state is not established, this column displays the BGP state. If the state is established, this column displays the number of prefixes that the local FortiGate received from that neighbor.”

Therefore, because neighbor 100.64.2.254 is in Active state, the correct conclusion is that the BGP adjacency cannot form because the TCP session could not be established.

Why the other options are wrong:

A is wrong because BGP can establish adjacencies with multiple neighbors independently; one established neighbor does not block another

C is wrong because BGP adjacency is not established based on neighbor “priority”; the output shows adjacency is established because the session completed and prefixes were exchanged

D is wrong because having two neighbors in the same remote AS is valid in BGP and does not prevent adjacency formation

So the verified answer is: B.