NSE4_FGT_AD-7.6 Exam Dumps : Fortinet NSE 4 - FortiOS 7.6 Administrator

In FortiOS 7.6, SD-WAN Performance SLAs are used to measure link quality and influence SD-WAN rule decisions. The following three statements are true.

C. All the SLA targets can be configured.

True

SD-WAN Performance SLAs allow administrators to configure:

Latency

Jitter

Packet loss

Mean Opinion Score (MOS) (for voice)

Threshold values for these metrics are fully configurable per SLA.

This is explicitly documented in the SD-WAN Performance SLA configuration section.

D. They are applied in an SD-WAN rule lowest cost strategy.

True

Performance SLAs are commonly used with the Lowest Cost (SLA-based) strategy.

In this strategy:

FortiGate selects the lowest-cost link that meets the SLA requirements.

If a link violates the SLA, it is excluded from selection.

E. They can be measured actively or passively.

True

FortiOS supports:

Active probing (synthetic probes such as ping/HTTP)

Passive measurement (based on real traffic statistics)

Administrators can choose how SLAs are measured depending on the deployment and requirements.

Why the other options are incorrect

A. They rely on session loss and jitter.

Incorrect

SLAs measure packet loss, latency, and jitter.

Session loss is not an SLA metric in FortiOS.

B. They monitor the state of the FortiGate device.

Incorrect

Performance SLAs monitor link quality, not FortiGate system health or device state.

According to the FortiOS 7.6 Administrator Study Guide and official documentation, SD-WAN rules (services) determine the path selection for traffic matching specific criteria. Version 7.6 provides specific flexibility regarding how these strategies handle multiple member interfaces.

First, Manual with load balancing (Statement B) is a valid configuration. In the Manual strategy, the administrator orders interfaces by preference, but by enabling the Load balancing toggle, the FortiGate can distribute traffic across all members that are up.

Second, the Lowest Cost (SLA) strategy has been enhanced to support two modes. When the load balancing option is disabled, it acts as Lowest Cost (SLA) without load balancing (Statement A), selecting the single lowest-cost link that meets the SLA. Alternatively, by enabling the toggle, it functions as Lowest Cost (SLA) with load balancing (Statement D), where the FortiGate distributes traffic across all interfaces that satisfy the SLA target, regardless of their individual costs.

Statements C and E are incorrect because " Lowest Quality " is not a recognized SD-WAN strategy, and the Best Quality strategy is specifically a priority-based selection for a single " best " link, meaning the load balancing toggle is not available in the GUI when this mode is selected.

“You can configure the fail-open setting under config ips global to control how the IPS engine behaves when the IPS socket buffer is full .”

“If the IPS engine does not have enough memory to build more sessions , the fail-open setting determines whether the FortiGate should drop the sessions or bypass the sessions without inspection .”

“It is important to understand that the IPS fail-open setting is not just for conserve mode—it kicks in whenever IPS fails. Most failures are due to a high CPU issue or a high memory (conserve mode) issue.”

Technical Deep Dive:

The correct answer is A .

The log text says:

logdesc= " IPS session scan paused "

action= " drop "

msg= " IPS session scan, enter fail open mode "

That combination indicates an IPS failure condition , specifically the condition described in the guide where the IPS socket buffer is full and the IPS engine lacks enough memory/resources to build additional sessions. In that state, FortiGate applies the configured IPS fail-open behavior . Since the log shows action= " drop " , the device is not bypassing those new sessions; it is dropping them.

Why the other choices are wrong:

B is wrong because the guide ties fail-open to socket buffer/resource exhaustion , not packet decode failure.

C is wrong because this is not evidence of a manual diagnostic pause.

D is wrong because the study guide does not associate this log with dirty-flag packet reevaluation.

Operationally, this usually points to high memory , high CPU , or conserve-mode pressure affecting the IPS engine. Useful checks are:

get system performance status

diagnose hardware sysinfo conserve

diagnose sys top

Those help confirm whether the IPS issue is being driven by memory pressure or CPU exhaustion.