The correct answer is A .

The study guide explains the IKEv2 exchange order very clearly:

“The initial exchanges are: IKE_SA_INIT and IKE_AUTH.”

“Create_Child_SA exchange: Creates a new child SA or rekeys an existing child SA.”

It also states:

“After successful IKE_SA_INIT and IKE_AUTH exchanges, the CHILD_SA exchange takes place. In this exchange, the peers negotiate the CHILD_SA and the traffic selectors — traffic selector responder (TSr) and traffic selector initiator (TSi).”

That is why A is correct: if the tunnel was initially brought up successfully , then the initial exchanges already succeeded. A later problem during CREATE_CHILD_SA , especially with traffic selectors/phase 2 selectors , can cause the tunnel to fail during rekey or child-SA renegotiation.

Why the other options are wrong:

B is wrong because proposal mismatch for the IKE SA is handled during IKE_SA_INIT , not after the tunnel is already up. The study guide says IKE_SA_INIT negotiates the security settings to protect the IKE traffic

C is wrong because a pre-shared key mismatch is part of authentication and would prevent successful initial establishment during IKE_AUTH . The study guide shows that after IKE_AUTH, “authentication succeeded” and “established IKE SA” when it works

D is wrong because a Diffie-Hellman mismatch belongs to IKE_SA_INIT , which happens before the tunnel comes up. The study guide also states: “By IKEv2 design, no Diffie-Hellman public key is exchanged during an IKE_AUTH exchange.”

So the verified answer is: A .

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.

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.

Setting unsupported-ssl-version to block prevents HTTPS connections from continuing when the negotiated SSL/TLS version falls below the version permitted by the inspection profile. The Enterprise Firewall 7.6 Administrator Study Guide demonstrates this hardening control together with an appropriate minimum version and explains that it can block obsolete TLS versions while accepting newer, secure versions. Therefore, option A is correct.

Enabling Server certificate SNI check protects against hostname inconsistencies between the client-supplied SNI and the server certificate. The FortiOS guide explains that, when enabled, FortiGate uses the certificate’s CN when the SNI hostname does not match any CN or SAN entry. This reduces the risk of SNI-based filtering evasion or domain-fronting behavior, making option B correct.

Setting untrusted certificates to Ignore weakens security. FortiGate proceeds with the SSL session regardless of whether the server certificate is trusted. Option C is therefore incorrect.

SSL 3.0 is obsolete and vulnerable, including exposure to POODLE-style attacks. Setting it as the minimum permitted version does not constitute secure hardening. A hardened profile should normally require TLS 1.2 or later, so option D is incorrect.

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.

The output on FGT-01 confirms that the device is actively encapsulating traffic and sending it as ESP packets (Protocol 50) out of port1 towards the IP address 97.86.16.52. The logs show outgoing packets, which confirms FGT-01 is attempting to initiate or maintain the tunnel and that NAT-Traversal is not being used (as it uses raw ESP).

The output on FGT-02 , however, displays (no packets captured). This is significant because the sniffer command diagnose sniffer packet any ' esp ' captures traffic at the network interface level (ingress), regardless of whether a matching VPN configuration exists on the receiving unit. The absence of packets proves that the ESP traffic generated by FGT-01 is physically not arriving at FGT-02 ' s interface.

This behavior is explained by two primary factors:

Option A (Blocking): An intermediate device, such as an ISP router or firewall, is dropping Protocol 50 traffic. Unlike UDP 500/4500, raw ESP is often blocked by default on many networks or legacy devices.

Option C (Routing/Misconfiguration): If the administrator configured the wrong remote peer IP on FGT-01 , the packets are being routed to a different destination entirely. Consequently, they never arrive at FGT-02 to be captured.

Option B is incorrect because even without a configured VPN tunnel, the sniffer would still display the incoming ESP packets if they were reaching the interface. Option D is incorrect because FGT-01 is sending ESP, making ' esp ' the correct filter.

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