What NSE4_FGT_AD-7.6 Questions and Answers feature?

Exact Extract:

“In IKEv1, there are two possible modes in which the IKE SA negotiation can take place: main, and aggressive mode. Settings on both ends must agree; otherwise, phase 1 negotiation fails and both IPsec peers are not able to establish a secure channel.”

“When both peers know each other ' s IP address or FQDN, you may want to use main mode to take advantage of its more secure negotiation. In this case, FortiGate can identify the remote peer by its IP address and, as a result, associate it with the correct IPsec tunnel.”

“FortiGate supports three DPD modes... The default DPD mode is On Demand .”

“ Diffie-Hellman (DH) ... is used during IKE SA negotiation. The use of DH in phase 1 is mandatory and can’t be disabled . You must select at least one DH group.”

Technical Deep Dive:

The correct answers are B and C .

B is correct because phase 1 fails when IKE mode settings do not match between peers. The study guide explicitly says phase 1 settings on both ends must agree. Since this is a static site-to-site tunnel and both peers know each other’s IP addresses, Main (ID protection) is the appropriate mode.

C is correct based on the exhibit: BR1-FGT appears bound to the wrong physical interface. The screenshot shows Interface = port1 , while the diagram/answer choice indicates the tunnel should be using port2 . If the phase 1 is bound to the wrong WAN interface, FortiGate sends IKE packets out the wrong path and phase 1 will not come up.

Why the others are not the fix:

A is not correct because DH is mandatory in phase 1. The issue is not “disable DH group 2” by itself; the real requirement is that the peers negotiate a compatible proposal. The option as written is not the proper corrective action from the guide.

D is not correct because DPD does not determine whether phase 1 can initially establish. It is a tunnel health/failure-detection feature after negotiation behavior, and On Demand is already the default mode.

“To perform SSL inspection on traffic flowing through the FortiGate device, you must allow the traffic with a firewall policy and apply an SSL inspection profile to the policy. Note that an SSL inspection profile alone will not trigger a security inspection. You must combine it with other security profiles like Antivirus, Web Filter, Application Control, or IPS.”

“By default, firewall policies are set with the no-inspection SSL profile. Therefore, any encrypted traffic flows through uninspected... For antivirus or IPS control, you should use a deep-inspection profile. ”

“When you use deep inspection, FortiGate impersonates the recipient of the originating SSL session, and then decrypts and inspects the content to find threats and block them . It then re-encrypts the content and sends it to the real recipient. Deep inspection protects from attacks that use HTTPS and other commonly used SSL-encrypted protocols...”

Technical Deep Dive:

The correct answer is D . HTTP and FTP are working because FortiGate can inspect those payloads directly with the antivirus profile. HTTPS is different because the traffic is encrypted. If the firewall policy uses only certificate inspection or another non-decrypting SSL mode, FortiGate can identify certificate/SNI information, but it cannot see the downloaded file contents. Without decrypting the HTTPS session, the antivirus engine never receives the payload to scan, so EICAR or other malware can pass.

Why the other options are wrong:

A is not the issue here. The exhibit shows the antivirus profile and policy are already aligned for proxy-based operation, and the failure is specific to HTTPS visibility.

B is wrong because web filter is not required for antivirus scanning.

C is wrong because firewall policies commonly use ACCEPT with security profiles; the antivirus engine can still block the file after policy match. The study guide explicitly says ACCEPT allows the session and then applies antivirus scanning and other packet-processing features.

To fix it, apply deep-inspection on the firewall policy:

config firewall policy

edit < policy-id >

set ssl-ssh-profile " deep-inspection "

set av-profile " HTTP_AV_Profile "

next

end

On real FortiGate hardware, this also has performance implications. Simple flow handling can often stay on accelerated paths, but full SSL deep inspection forces decryption and content scanning through the inspection engine, increasing CPU/WAD workload.

“To reduce the number of log messages generated and improve performance, you can enable a session table entry of dropped traffic. This creates the denied session in the session table and, if the session is denied, all packets for that session are also denied. This ensures that FortiGate does not have to perform a policy lookup for each new packet matching the denied session, which reduces CPU usage and log generation.”

“The CLI command is ses-denied-traffic. You can also set the duration for block sessions. This determines how long a session will be kept in the session table by setting block-session-timer in the CLI. By default, it is set to 30 seconds.”

Technical Deep Dive:

The correct answers are A and B .

When set ses-denied-traffic enable is configured, FortiGate creates a session-table entry for denied traffic . That means once traffic is denied, subsequent packets that belong to the same denied flow do not need a full policy lookup again. FortiGate can drop them immediately based on the existing denied-session entry. That directly confirms B .

Because FortiGate no longer re-evaluates every repeated denied packet in the same way, the device generates fewer logs and uses less CPU for repeated denied traffic. That is exactly why A is also correct.

Why the other two are wrong:

C is incorrect because block-session-timer 30 means 30 seconds , not 30 minutes. The denied session entry is kept in the session table for that duration.

D is incorrect because these settings do not disable session helpers. They only control how denied traffic is tracked in the session table.

In operational terms, this feature is useful when a host repeatedly retries traffic that FortiGate is already denying. Instead of doing a fresh lookup for every retry, FortiGate caches the denied decision temporarily and drops the repeated packets faster.