By default, local-out traffic does not use SD-WAN → FortiGate normally sends local-out traffic (e.g., DNS, NTP, FortiGuard updates) directly through its interfaces without applying SD-WAN rules.
You must configure each local-out feature individually to use SD-WAN → To steer local-out traffic via SD-WAN, you must explicitly configure the desired local-out features (e.g., DNS, FortiGuard, CAPWAP) to use SD-WAN rules.

The use of SLA targets is specific to certain SD-WAN strategies. The "Lowest Cost (SLA)" and
"Maximize Bandwidth (SLA)" strategies are explicitly designed to use the configured SLA targets to make routing decisions. The "Best Quality" strategy uses performance metrics but does not necessarily require or reference SLA targets in the same way, while "Manual" does not use metrics at all for path selection.
This is a core function of SD-WAN rules with SLA targets. The purpose of configuring an SLA target with specific thresholds for latency, jitter, and packet loss is to define what is considered
"acceptable" performance for an application. SD-WAN rules then use these targets to check if the members (interfaces) meet these requirements before a flow is steered over them, ensuring that a preferred path still offers a good user experience.
FortiGate allows for a single SD-WAN rule to reference multiple, different performance SLAs. This is crucial for complex deployments where a single SD-WAN rule needs to handle traffic for multiple applications that have distinct performance requirements. For example, a single rule might direct VoIP traffic based on one performance SLA with strict latency/jitter targets, while simultaneously handling general web traffic using another performance SLA with more lenient requirements.

According to the SD-WAN 7.6 Core Administrator curriculum and the provided exhibits, the traffic steering decision is determined by the interaction between the Lowest Cost (SLA) strategy and the link health status reported in the event logs.
Rule Strategy (Lowest Cost SLA): The SD-WAN rule configuration for ID 1 (named Critical-DIA) is set to mode sla. In this mode, the FortiGate will only steer traffic through member interfaces that satisfy the assigned Performance SLA targets.
Member Preference: The rule defines priority-members 1 2. This means that under normal conditions (where both links are healthy), Member 1 (port1) is the preferred interface because it is listed first.
Event Log Analysis:
The first log message explicitly states: "Member status changed. Member out-of-sla." for Member
1. This indicates that port1 has exceeded one of the thresholds (latency, jitter, or packet loss) defined in the Corp_HC health check.
The second log confirms: "Number of pass member changed. New Value: 1, Old Value: 2". This verifies that while there were previously two links passing the SLA, now only one link (Member
2/port2) remains in a passing state.
Steering Decision: Because the rule strategy is mode sla and the primary preferred member (port1) is now out-of-sla, the FortiGate immediately disqualifies Member 1 from the selection pool for this specific rule. It then moves to the next available member in the priority list that does satisfy the SLA, which is Member 2 (port2).

Routing: For a packet to even be considered by the SD-WAN engine, there must be a matching route in the Forwarding Information Base (FIB). Usually, this is a static route where the destination is the network you want to reach, and the gateway interface is set to the SD-WAN virtual interface (or a specific SD-WAN zone). If there is no route pointing to SD-WAN, the FortiGate will use other routing table entries (like a standard static route) and bypass the SD- WAN rule-based steering logic entirely.
Interfaces: You must first define the physical or logical interfaces (such as ISP links, LTE, or VPN tunnels) as SD-WAN members. These members are then typically grouped into SD-WAN Zones.
Without designated member interfaces, there is no "pool" of links for the SD-WAN rules to select from.
Firewall Policies: In FortiOS, no traffic is allowed to pass through the device unless a Firewall Policy permits it. To steer traffic, you must have a policy where the Incoming Interface is the internal network and the Outgoing Interface is the SD-WAN zone (or the virtual-wan-link). The SD- WAN rule selection happens during the "Dirty" session state, which requires a policy match to proceed with the session creation.

According to the SD-WAN 7.6 Core Administrator curriculum and the provided exhibits, the traffic steering decision is determined by the interaction between the Lowest Cost (SLA) strategy and the link health status reported in the event logs.
Rule Strategy (Lowest Cost SLA): The SD-WAN rule configuration for ID 1 (named Critical-DIA) is set to mode sla. In this mode, the FortiGate will only steer traffic through member interfaces that satisfy the assigned Performance SLA targets.
Member Preference: The rule defines priority-members 1 2. This means that under normal conditions (where both links are healthy), Member 1 (port1) is the preferred interface because it is listed first.
Event Log Analysis:
The first log message explicitly states: "Member status changed. Member out-of-sla." for Member 1. This indicates that port1 has exceeded one of the thresholds (latency, jitter, or packet loss) defined in the Corp_HC health check.
The second log confirms: "Number of pass member changed. New Value: 1, Old Value: 2". This verifies that while there were previously two links passing the SLA, now only one link (Member 2/port2) remains in a passing state.
Steering Decision: Because the rule strategy is mode sla and the primary preferred member (port1) is now out- of-sla, the FortiGate immediately disqualifies Member 1 from the selection pool for this specific rule. It then moves to the next available member in the priority list that does satisfy the SLA, which is Member 2 (port2).
Why other options are incorrect:
Option A: FortiGate will not load balance or choose between both links because port1 is currently ineligible due to the SLA failure.
Option B: Steering to port1 would violate the "Lowest Cost (SLA)" rule logic, as that link is no longer meeting the required health standards.
Option D: FortiGate does not "skip" the rule unless no members meet the SLA and there is no fallback configured; in this scenario, port2 is still passing and available.