You have configured the performance SLA with the probe mode as Prefer Passive. What are two observable impacts of this configuration? (Choose two.)
Select an option, then click Submit answer.
Reference / correct answer:
FortiGate passively monitors the member if TCP traffic is passing through the member.
Most accepted answer: A. FortiGate passively monitors the member if TCP traffic is passing through the member.
Community votes: A=3, D=3
Selected Answer: AD AD are correct. From Page 138 of SD-WAN 7.4 Architect: A - "In prefer passive monitoring, FortiGate uses passive monitoring if there is TCP traffic through the member..." D - "Note that changes in member state are detected only when FortiGate is doing active monitoring..." B is incorrect - there is a 3-minute timer to trigger active mode if TCP traffic is not observed, but if in active mode, it falls back to passive mode immediately once recognizing that traffic is passing through the member. C - FortiGate does not use ICMP for passive monitoring E - FortiGate CANNOT offload traffic that is associated with a member in passive monitoring mode - auto-asic-offload must be disabled on associated firewall policies. upvoted 4 times
Selected Answer: AD The correct answers are: A. FortiGate passively monitors the member if TCP traffic is passing through the member. D. During passive monitoring, the SLA performance rule cannot detect dead members. 🔹 Why A is correct In Prefer Passive mode, FortiGate doesn’t send active probes (ICMP, UDP, HTTP) unless needed. Instead, it extracts performance metrics from live traffic. Supported protocols for passive monitoring are TCP/UDP sessions (e.g., measuring latency/jitter from sequence numbers and acknowledgments). 🔹 Why D is correct Passive mode can only measure if user traffic exists. If no user traffic passes through that link, FortiGate cannot tell whether the link is dead or just idle. Therefore, SLA cannot detect member “dead” status in passive mode — only active probing can. ❌ Why the others are wrong B: No fixed “3-minute fallback” — fallback depends on SLA thresholds and lack of traffic, not a timer. C: Passive monitoring does not use ICMP pings; ICMP-based checks require active probes. E: Hardware offload has nothing to do with passive SLA monitoring. upvoted 2 times
Selected Answer: AD I think AD are correct upvoted 2 times