grceng.academy
Review lab 40 bonus XP

Review the switching sign-off

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Objectives

The installer has submitted six independent sign-off claims. The cover note says all six prove segmentation because every device has a VLAN number.

Accept technically sound claims and reject false assurance. Judge each line on its own stated evidence, not on whether another line might compensate for it.

Verdicts are accept or reject. Every rejection needs one reason code from: flood-scope | vlan-not-policy | loop-safety | arp-trust.

Independent handover claims

ES-1  A source MAC observed on p7 in VLAN 20 creates a dynamic entry for that source and ingress port in VLAN 20.
ES-2  Unknown unicast from p7 in VLAN 20 must be copied to VLAN 30 access ports to discover the destination.
ES-3  Reception and clinical devices have different VLAN IDs, so all routed clinical administration access is denied without any policy rules.
ES-4  Both trunk ends explicitly allow only the required tagged data VLANs and agree on an unused native VLAN with no endpoint ports.
ES-5  Two redundant inter-switch links both forward in the same VLAN; disabling spanning tree prevents broadcast loops.
ES-6  A gateway ARP reply is authenticated by its sender IP field, so forged gateway claims cannot poison neighbour caches.

Checks the server runs (3)

  • Every line in the fixture carries a verdict
  • Accept and reject land on the right lines
  • Each rejection cites a valid reason code

Check names are all you see here: the expectations that decide pass or fail, and the reference solution, stay on the server.

Step-by-step hints

The guided walkthrough, in full. It is free: no XP cost, and it does not touch the paid hint ladder or the reveal gate.

  1. Step 1

    Read the request before the artefact

    Read the claims as assertions about mechanisms. Decide which configuration or packet observation would make each assertion defensible.

  2. Step 2

    Judge every line, including the boring ones

    Assign one verdict to every independent claim. Do not leave routine-looking statements unreviewed.

    Every line in the fixture carries a verdict

  3. Step 3

    Separate what is wrong from what is merely ugly

    Trace the learning field and flooding boundary, then distinguish logical membership from permission. Check whether the claimed loop and neighbour protections exist in the named mechanism.

    Accept and reject land on the right lines

  4. Step 4

    Say why, in the vocabulary the programme uses

    For each rejected claim, select the code describing its root misconception. Leave the reason blank for sound claims rather than adding a speculative concern.

    Each rejection cites a valid reason code

Rules summary

  • XP on pass

    40 bonus XP the first time every check goes green.

  • Paid hints

    2 available. Each costs 25% of the lab XP (about 10 XP).

  • Reveal solution

    Scores 0 XP and unlocks only after 3 check runs.

  • Attempt cap

    60 check runs per learner. The runner warns you in the last 10.

  • Drafts

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  • Walkthrough

    Always free and never penalised: use it before spending a hint.