Pass the Fortinet Network Security Expert NSE4_FGT_AD-7.6 Questions and answers with Dumpstech

Phase 1 being up confirms the two FortiGate devices can authenticate and build the IKE SA. Phase 2 failing indicates the IPsec (Quick Mode) SA negotiation is failing due to mismatched Phase 2 parameters.

From the exhibit, the Phase 2 mismatches that would prevent SA establishment are:

1) Phase 2 selectors must mirror each other (Proxy IDs)

HQ-NGFW Phase 2 selector shows:

Local: 10.0.11.0/24

Remote: 172.20.1.0/24

BR1-FGT Phase 2 selector shows:

Local: 172.20.1.0/24

Remote: 10.11.0.0/24 ⟵ does not match HQ’s local subnet (10.0.11.0/24)

In FortiOS, Phase 2 comes up only when the peers’ selectors (proxy IDs) match as opposite pairs (local on one side = remote on the other).

✅ Fix: A. On BR1-FGT, set Remote Address to 10.0.11.0/255.255.255.0.

2) Phase 2 proposal must match (encryption/authentication)

HQ-NGFW shows encryption AES128 (with SHA1)

BR1-FGT shows encryption AES256 (with SHA1)

For Phase 2 to establish, both peers must have at least one common proposal (same encryption and authentication settings). With one side set to AES128 and the other to AES256, there is no match.

✅ Fix: D. On HQ-NGFW, set Encryption to AES256.

Why the other options are not correct

B. Enable Diffie-Hellman Group 2: The exhibit’s mismatch is not resolved by adding DH group 2, and DH group must match when PFS is enabled. This option does not align the peers based on what’s shown.

C. Set Seconds to 43200: Phase 2 lifetime mismatches typically do not prevent Phase 2 from coming up (the negotiated lifetime can be adjusted by the peers). The hard blockers here are the selectors and proposal mismatch.

In the FortiGate Cloud-Native Firewall (CNF) for AWS architecture, traffic from workloads (such as an EC2 instance) in the customer VPC is redirected to the security service (FortiGate CNF) using AWS Gateway Load Balancer (GWLB) technology.

The key AWS component that must exist inside the customer VPC to steer workload traffic to the GWLB is the:

Gateway Load Balancer Endpoint (GWLBe)

This endpoint is what the customer VPC routes point to (for example, default route or subnet route entries), enabling transparent insertion of the FortiGate CNF inspection path for EC2 traffic.

Why the other options are not correct:

A: CNF does not “create the customer VPC” (that is customer-owned), and “GWLBe” is the only relevant created item here, not the whole VPC.

C: Customer VPC is not created by CNF, and GWLB is typically part of the CNF service side; the question specifically asks what must be created to handle traffic from the EC2 instance (that requires GWLBe in the customer VPC).

D: CNF does not create the Internet Gateway (IGW) in the customer VPC, and IGW is not the required CNF-created component for steering traffic to FortiGate CNF.

Based on the exhibit and FortiOS 7.6 Active Authentication (captive portal) behavior, the most likely reason the user is not presented with a login prompt is that DNS is missing from the firewall policy.

What the exhibit shows

The firewall policy configured for active authentication includes:

Source: HQ_SUBNET and Remote-users

Destination: all

Services:

HTTP

HTTPS

ALL_ICMP

Security Profiles: Web filter and SSL inspection enabled

Authentication: Active (user group referenced)

DNS is not included as a service in the policy.

Why DNS is required for active authentication

In FortiOS 7.6, active authentication (captive portal) works as follows:

The user attempts to access a website using a URL (for example, www.example.com).

The client must first perform a DNS lookup to resolve the domain name.

FortiGate intercepts the initial HTTP/HTTPS request and redirects the user to the authentication portal.

If DNS traffic is blocked or not allowed:

The hostname cannot be resolved.

The HTTP/HTTPS request never properly occurs.

FortiGate has nothing to intercept, so the login prompt is never triggered.

This is explicitly documented in the FortiOS 7.6 Authentication and Captive Portal requirements, which state that DNS must be permitted for captive portal–based authentication to function correctly.

Why the other options are incorrect

A. No matching user account exists for this user

Incorrect.

If the user account did not exist, the login page would still appear, but authentication would fail after credentials are entered.

B. The Remote-users group must be set up correctly in the FSSO configuration

Incorrect.

This policy is using active authentication, not FSSO.

FSSO configuration is irrelevant for active authentication login prompts.

C. The Remote-users group is not added to the Destination

Incorrect.

User groups are applied in the Source field for authentication-based policies.

Destination does not accept user groups.

When the Application sensor receives traffic on that port, the protocol decoder will try to determine if the received data matches the HTTPS traffic In this case it will not match because it is P2P traffic, so this will class as violation and blocked The protocol decoder also try to determine what type of traffic it is, and even if it could not figure out it is P2P traffic, it still count as a violation because even though it does not know what it is, it knows for fact it is not HTTPS

Based on the exhibit and FortiOS 7.6 Active Authentication (captive portal) behavior, the most likely reason the user is not presented with a login prompt is that DNS is missing from the firewall policy.

What the exhibit shows

The firewall policy configured for active authentication includes:

Source: HQ_SUBNET and Remote-users

Destination: all

Services:

HTTP

HTTPS

ALL_ICMP

Security Profiles: Web filter and SSL inspection enabled

Authentication: Active (user group referenced)

DNS is not included as a service in the policy.

Why DNS is required for active authentication

In FortiOS 7.6, active authentication (captive portal) works as follows:

The user attempts to access a website using a URL (for example, www.example.com).

The client must first perform a DNS lookup to resolve the domain name.

FortiGate intercepts the initial HTTP/HTTPS request and redirects the user to the authentication portal.

If DNS traffic is blocked or not allowed:

The hostname cannot be resolved.

The HTTP/HTTPS request never properly occurs.

FortiGate has nothing to intercept, so the login prompt is never triggered.

This is explicitly documented in the FortiOS 7.6 Authentication and Captive Portal requirements, which state that DNS must be permitted for captive portal–based authentication to function correctly.

Why the other options are incorrect

A. No matching user account exists for this user

Incorrect.

If the user account did not exist, the login page would still appear, but authentication would fail after credentials are entered.

B. The Remote-users group must be set up correctly in the FSSO configuration

Incorrect.

This policy is using active authentication, not FSSO.

FSSO configuration is irrelevant for active authentication login prompts.

C. The Remote-users group is not added to the Destination

Incorrect.

User groups are applied in the Source field for authentication-based policies.

Destination does not accept user groups.

From the current HA status, HQ-NGFW-1 is the primary and HQ-NGFW-2 is the secondary.

The administrator then changes these HA parameters:

HQ-NGFW-1: set override disable, set priority 90

HQ-NGFW-2: set override enable, set priority 110

In FGCP (A-P mode), the override (preemption) feature controls whether a higher-priority unit is allowed to take over the primary role.

When override is enabled, the cluster will prefer (and can re-elect) the unit with the highest device priority to become primary (preempting a lower-priority primary when conditions trigger re-election behavior as defined by FGCP).

Here, HQ-NGFW-2 has:

override enabled

higher priority (110) than HQ-NGFW-1 (90)

Therefore, the expected result is that HQ-NGFW-2 becomes the primary.

Why the other options are incorrect:

B is incorrect because it claims HQ-NGFW-2 has lower priority (it is higher: 110 > 90).

C is incorrect because a mismatch in the override setting is not what causes the “configuration out of sync” condition shown in get system ha status (that is about synchronized configuration databases, not a requirement that override values must match to remain in-sync).

D is incorrect because HA settings like override/priority are not synchronized in the way regular configuration objects are; they are device-level HA parameters.

According to the FortiOS 7.6 Administration Guide and Security Fabric documentation, automation stitches are designed to automate responses to security and system events across the network. A core characteristic of these stitches is their flexibility in action execution; specifically, multiple actions can run in parallel (Statement C). While the system allows for sequential execution with configurable delays between actions, the default behavior or configuration option allows for simultaneous responses, such as sending an email notification while simultaneously triggering a webhook or quarantining a host.

Furthermore, triggers can involve external connectors (Statement D). While many triggers are local to the FortiGate (such as reboots or log events), the Security Fabric allows the FortiGate to monitor and react to events from external components like FortiAnalyzer, FortiSIEM, or FortiClient EMS. For example, a FortiAnalyzer event handler can act as the trigger for a stitch on the root FortiGate. Statement A is incorrect because actions can target external systems like AWS Lambda or Slack which are not internal Fabric devices. Statement B is incorrect because each automation stitch is typically defined by a single trigger, though that trigger itself can be broad (e.g., "Any Security Rating Notification").

Phase 1 being up confirms the two FortiGate devices can authenticate and build the IKE SA. Phase 2 failing indicates the IPsec (Quick Mode) SA negotiation is failing due to mismatched Phase 2 parameters.

From the exhibit, the Phase 2 mismatches that would prevent SA establishment are:

1) Phase 2 selectors must mirror each other (Proxy IDs)

HQ-NGFW Phase 2 selector shows:

Local: 10.0.11.0/24

Remote: 172.20.1.0/24

BR1-FGT Phase 2 selector shows:

Local: 172.20.1.0/24

Remote: 10.11.0.0/24 ⟵ does not match HQ’s local subnet (10.0.11.0/24)

In FortiOS, Phase 2 comes up only when the peers’ selectors (proxy IDs) match as opposite pairs (local on one side = remote on the other).

✅ Fix: A. On BR1-FGT, set Remote Address to 10.0.11.0/255.255.255.0.

2) Phase 2 proposal must match (encryption/authentication)

HQ-NGFW shows encryption AES128 (with SHA1)

BR1-FGT shows encryption AES256 (with SHA1)

For Phase 2 to establish, both peers must have at least one common proposal (same encryption and authentication settings). With one side set to AES128 and the other to AES256, there is no match.

✅ Fix: D. On HQ-NGFW, set Encryption to AES256.

Why the other options are not correct

B. Enable Diffie-Hellman Group 2: The exhibit’s mismatch is not resolved by adding DH group 2, and DH group must match when PFS is enabled. This option does not align the peers based on what’s shown.

C. Set Seconds to 43200: Phase 2 lifetime mismatches typically do not prevent Phase 2 from coming up (the negotiated lifetime can be adjusted by the peers). The hard blockers here are the selectors and proposal mismatch.