Knowledge check Network Troubleshooting & Recovery
14 questions in pool · live exam draws 6
N02
Q1 multiple-choice · layer-mindset When troubleshooting “Control Unit offline”, what’s the correct discipline for working through the diagnostic layers?
Source: N02 textbook §1 (The mindset — work the layers).
Explanation: Half of symptoms that look like application problems are physical-layer issues with a 5-second fix. Bottom-up discipline catches them fast. Top-down or symptom-jumping skips the cheap-fix layer.
Q2 multiple-choice · frfind-vs-ping What’s the key difference between FRFind finding a Control Unit and ping reaching it?
Source: N02 textbook §2 (Step 3 FRFind).
Explanation: FRFind verifies link-layer reachability via MAC/ARP, bypassing IP. Useful when DHCP gave the wrong IP or VLAN mismatch is in play. Ping requires IP to be functional. They diagnose different layers.
Q3 multiple-choice · locator-capp-gap Locator shows a Control Unit online but CAPP can’t connect. What’s the FIRST thing to check?
Source: N02 textbook §6 (Locator says online but CAPP can’t connect).
Explanation: Stale workspace IP (from a previous DHCP-renewed IP) is the most common cause. Locator’s discovery is fresh; CAPP’s workspace is whatever was last saved. Update the workspace IP and retry before more invasive steps.
Q4 multiple-choice · tcp-test A nc -zv 192.168.10.10 6543 test returns “Connection refused”. What does this mean?
Source: N02 textbook §2 (Step 6 TCP) and §4 (Firewall blocking).
Explanation: “Connection refused” = host reachable but no listener on that port. Different from “timeout” which suggests firewall blocking. Refused → restart Control Unit firmware; timeout → check firewall rule.
Q5 multiple-choice · dhcp-exhaustion A new Control Unit won’t get an IP from DHCP. The DHCP scope is 192.168.10.50-200 and the studio has 4 cameras, 2 lighting kits, 2 laptops. What’s the most likely cause?
Source: N02 textbook §3 (DHCP misbehavior).
Explanation: 151 addresses, 8 active devices — but DHCP scope exhaustion at the new device’s attempt typically means stale leases hold addresses. Recovery: expand scope or shorten lease time. The other answers are possible but lower probability.
Q6 multiple-choice · firewall-allow-all A new firewall rule has been added between main and lighting subnets and the studio is now mostly working again. What’s a common mistake to AVOID with this rule?
Source: N02 textbook §4 (Firewall blocking).
Explanation: allow any-any defeats the whole purpose of subnet isolation. The correct rule allows only specific protocols/ports needed (Art-Net UDP/6454, etc.). If specific rules don’t work, the issue isn’t firewall — keep diagnosing.
Q7 true-false · power-cycle-discipline “Power cycling everything” is a valid first response when a Control Unit shows offline.
Source: N02 textbook §1 + common mistakes (power-cycle as first response).
Explanation: Power cycle hides 60 % of root causes by making the symptom temporarily disappear, then it returns. Discipline: walk the 8-step tree first; power-cycle only after diagnostic shows it’s likely to help (Step 6 connection refused, suggesting hung listener).
Q8 multiple-choice · ap-isolation Locator shows zero Control Units from the operator’s WiFi-connected laptop, but FRFind from the same laptop finds them all. What’s most likely?
Source: N02 textbook §2 (Step 7 Locator).
Explanation: “AP isolation” (or “client isolation”) on WiFi prevents broadcast UDP from crossing between WiFi clients and wired devices. FRFind’s ARP-based discovery still works (link-layer). Locator’s broadcast doesn’t. Fix: disable client isolation on the AP.
Q9 multiple-choice · wifi-troubleshooting Operator reports CAPP is “sluggish today.” Network checks all green. Operator is on WiFi (laptop). What’s the first diagnostic?
Source: N02 textbook §5 (WiFi interference).
Explanation: Confirm WiFi is the cause before pursuing it. If wired works clean, WiFi is the bottleneck — investigate channel congestion or move to wired permanently. If wired also sluggish, the issue isn’t WiFi.
Q10 multiple-choice · escalation-packet Which item is NOT part of the proper PhotoRobot Support escalation packet?
Source: N02 textbook §7 (The escalation packet).
Explanation: Support is faster when given facts (what was tried, what was the result) than speculation. Distill to symptom + diagnostic data + recent changes. Let Support apply their judgment to facts, not to your guesses.
Q11 multiple-choice · regression-check After fixing a network issue, what’s the discipline for declaring the change safe?
Source: N02 textbook §8 (The “did I make it worse?” check).
Explanation: Reactive testing (waiting for complaints) is too late. Proactive regression check catches 20 % of fixes that introduced new problems. The checklist takes 5-10 minutes; the missed regression catches you in the middle of a shoot.
Q12 multiple-choice · layer-tools Match the layer to the right diagnostic tool:
Source: N02 textbook §1.
Explanation: FRFind is link-layer (ARP-based). Locator is application/discovery-layer. ping is IP. nc is transport. Each tool answers a different layer’s question; combining them works the stack.
Q13 multiple-choice · dhcp-conflict Two devices both claim 192.168.10.55 and have intermittent connection drops. Most likely cause?
Source: N02 textbook §3 (DHCP misbehavior — lease conflict).
Explanation: Most common cause of dual-claim: a device was statically configured with an IP that’s inside the DHCP scope. DHCP later assigned the same IP to another device. Fix: move statics OUTSIDE the DHCP scope (e.g., DHCP .50-.200, statics .10-.49).
Q14 multiple-choice · escalation-time After about how many minutes of diagnostics without root cause should the Network Specialist escalate to PhotoRobot Support?
Source: N02 anticipated Q&A.
Explanation: ~45 minutes is the rough budget. Past that, the studio’s lost-production cost exceeds the marginal benefit of more in-house diagnostic time. Escalation is a strength, not a failure. Arrive with clean diagnostic data and Support is fast.
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