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

The correct answer is B.

The study guide explicitly states: “IKE version 2 does not interoperate with IKE version 1, but they share enough of the header format that both versions can unambiguously operate over the same UDP port.”

That directly proves B.

Why the other options are wrong:

A is wrong because the study guide shows authentication methods as Asymmetric for IKEv2 and Symmetric for IKEv1

C is wrong because the study guide does not say they use the same TCP port; instead, it specifically says they can operate over the same UDP port

D is wrong because the study guide states: “IKEv2 does not use the concept of phase 1 or phase 2”, even though FortiOS CLI/GUI still uses those terms for configuration purposes

To determine the correct reasons for the adjacency failure, we must analyze the standard OSPF real-time debug output (diagnose ip router ospf all enable or diagnose sniffer packet) typically provided in this exam exhibit.

Analyze the Debug Output:

The debug output in this specific question scenario typically displays an incoming Hello packet line: OSPF: RECV[Hello]: ... auth-type 0 ...

" RECV " : Indicates the packet is coming from the Remote peer.

" auth-type 0 " : Indicates the Remote peer is sending " Null " (No) authentication.

Analyze the Failure:

The adjacency fails because the Local FortiGate is rejecting this packet.

If the Local FortiGate accepts " No Authentication " , it would match auth-type 0 and form the adjacency.

Since it is failing (and producing a debug log), the Local FortiGate must be expecting a different authentication type (Type 1 Cleartext or Type 2 MD5).

Evaluate the Options:

A. The remote peer has either OSPF cleartext or MD5 authentication configured.

Incorrect. The debug shows auth-type 0 (No Auth) coming from the remote peer.

B. There is an OSPF authentication configuration mismatch.

Correct. One side is sending " No Auth " (Remote), and the other expects " Auth " (Local). This is a definition of a mismatch.

C. The local FortiGate does not have OSPF authentication configured.

Incorrect. If the Local unit had " No Auth " configured, it would match the Remote ' s auth-type 0, and the adjacency would come up. The failure implies the Local unit does have auth configured.

D. The local FortiGate has either OSPF cleartext or MD5 authentication configured.

Correct. Because the Local unit is rejecting the " No Auth " packet from the remote peer, it confirms that the Local unit has authentication enabled (expecting Type 1 or 2).

Conclusion: The breakdown of the OSPF negotiation shows that the Remote peer is sending no authentication (Type 0), while the Local FortiGate expects authentication, resulting in a mismatch.

To capture encrypted IPsec phase 2 (ESP) traffic between two FortiGate devices, the correct protocol filter to use is ip proto 50. According to the Fortinet official sniffing and debugging documentation, ESP (Encapsulating Security Payload) is used for encrypted phase 2 payload transfer and always uses IP protocol number 50. Running the command diagnose sniffer packet any ' ip proto 50 '  captures only ESP packets, which represent the encrypted traffic—whether originating or transiting the device.

If there is no NAT device between FortiGates, ESP is not encapsulated in UDP (thus not on UDP port 4500; if NAT-T were required, packets would be UDP-encapsulated, but the scenario explicitly says NAT is not in use). UDP port 500 is for IKE control (negotiation) traffic, and AH (Authentication Header, ip proto 51) is not used for encryption in standard IPsec phase 2 with ESP.

This matches the official CLI reference from Fortinet for VPN and traffic analysis.

**

The Enterprise Firewall 7.6 Administrator Study Guide specifically warns that all-zero phase 2 selectors can introduce invalid paths during migrations, particularly when many routes are advertised across VPN tunnels or overlapping networks exist. One recommended mitigation is to use dynamic routing protocols to explicitly control which subnets are permitted and advertised through the tunnel, making A correct.

Fortinet also recommends defining the required encryption domains precisely in the phase 2 selectors. Specifying the exact network segments ensures that only designated traffic is eligible for the IPsec tunnel, making D correct. An IPsec aggregate provides redundancy but does not solve inappropriate route or encryption-domain selection. Assigning IP addresses to tunnel interfaces can support routing designs, but it is not the documented mitigation for invalid paths caused by overly broad all-zero selectors.

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The SD-WAN 7.6 Enterprise Administrator Study Guide identifies the recommended BGP-on-loopback IPsec settings. For branches, it specifies:

“Static tunnel type (remote end IP address is known).”

“net-device enable.”

Enabling net-device on the spoke creates a kernel interface for the tunnel. This assists with tunnel monitoring and management and is required to support ADVPN shortcut tunnels. Dynamic BGP establishes on-demand BGP peerings between spokes after an ADVPN shortcut is created; therefore, the spoke must support those dynamic shortcut interfaces. This makes option C correct.

The spoke should also configure localid. The FortiOS 7.6 Administrator Study Guide explains: “Local ID: if the peer accepts a specific peer ID, type that same peer ID in this field.” The local ID supplies the spoke’s IKE identity to the dial-up hub, allowing the hub to identify and authenticate the connecting spoke correctly. Therefore, option D is correct.

Option A reverses the recommended roles. The hub must use a dynamic tunnel type because it operates as the dial-up server and does not require every spoke’s changing public gateway address in advance.

Option B is also incorrect. The guide states: “There is no need to configure any tunnel IP address, so the IKE Mode Config is not used.” BGP on loopback uses the loopback address and exchange-interface-ip instead of IKE mode configuration.

To understand why Type 5 LSAs (AS External LSAs) are missing from the Link-State Database (LSDB), we must look at how OSPF generates and propagates them:

A. There is no autonomous system border router (ASBR) in the network:

Reason: Type 5 LSAs are exclusively generated by an ASBR to advertise routes redistributed from other protocols (like Static, BGP, or RIP) into the OSPF domain. If no router is configured to redistribute external routes (acting as an ASBR), no Type 5 LSAs are created in the first place.

C. The local router is located in a stub area:

Reason: By definition, a Stub Area (and a Totally Stubby Area) prevents Type 5 LSAs from entering. The Area Border Router (ABR) connecting the stub area to the backbone filters out all Type 5 LSAs to reduce the size of the LSDB and routing table for routers inside that area. Instead, a default route is usually injected.

Why other options are incorrect:

B: While database filtering exists, standard prefix-list filtering typically affects the routing table (RIB) generation, not the underlying LSDB propagation of Type 5 LSAs, or it is less common than the architectural reasons (Stub/No ASBR).

D: IP Protocol 89 is the transport for OSPF itself. If this were blocked, the OSPF adjacency would not form at all, meaning the router would receive no LSAs (Type 1, 2, etc.), not specifically just Type 5.

The correct answers are B and D.

The study guide explains that expectation sessions are pinhole sessions created by session helpers for protocols such as FTP that need additional negotiated connections. It states: “FortiGate created an expectation session and opened the pinhole port for the expected return traffic” and also shows that the firewall “creates an expected (pinhole) session to allow the traffic”

That makes D correct.

For B, the study guide explains the gwy= field in session output: the first value is the gateway to the destination, and the second is the gateway to the source

In the exhibit, the original-direction traffic is DNATed here:

hook=pre dir=org act=dnat 10.171.121.38:0- > 10.200.1.1:60426(10.0.1.10:50365)

So the destination after DNAT is the internal host 10.0.1.10, and the session’s first gwy value corresponds to the next hop toward that destination. That makes B correct.

Why the other options are wrong:

A is wrong because this is an expectation/session-helper behavior, not an IPS-engine-created session. The study guide ties expectation sessions to helpers such as FTP, not IPS.

C is wrong because 10.200.1.1 is the translated address used before DNAT, not the next hop used to forward the original-direction traffic after translation to the internal destination.

So the verified answers are: B, D.

The correct answers are B and D.

The study guide explains that in the SP Login Dump section, FortiGate is acting as the service provider (SP), and that you should read these fields:

“The IdP SSO URL, from the setting idp-single-sign-on-url in the FortiGate configuration”

“The SP SSO URL, from the setting single-sign-on-url in the FortiGate configuration”

“The IdP Entity ID, from the setting id-entity-id in the FortiGate configuration”

“The SP Entity ID, from the setting entity-id setting in the FortiGate configuration”

In the exhibit:

Destination= " https://10.1.10.2/saml-idp/nst/login/ " → this is the IdP SSO URL

< lasso:RemoteProviderID > http://10.1.10.2/samlidp/nst/metadata/ < /lasso:RemoteProviderID > → this is the IdP Entity ID

AssertionConsumerServiceURL= " https://10.1.10.254:1003/remote/saml/login/ " → this is the SP SSO URL

< saml:Issuer > https://10.1.10.254:1003/remote/saml/metadata/ < /saml:Issuer > → this is the SP Entity ID

The same study-guide example shows this exact mapping pattern, where:

Destination points to the IdP

AssertionConsumerServiceURL and Issuer point to the SP

Therefore:

10.1.10.2 is the IdP → D

10.1.10.254 is the SP → B

So the verified answers are: B, D.