grceng.academy
YAML lab 60 bonus XP

Build the segmented address plan

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Objectives

The office lead offers four equal /25s and asks you to put guests and servers in one VLAN to save addresses. The signed requirements instead demand four separate zones, minimally sized, with a gateway in each.

Complete the plan using the allocation algorithm in the fixture. Include exact gateway and broadcast values, both remaining reserved CIDRs, the approved application service, and a short explanation of where inter-zone enforcement occurs. This is project step one; the next lab reviews candidate firewall changes against this plan.

Signed address and segmentation requirements

base: 10.42.0.0/23
order: staff, guests, servers, management
endpoint_counts: 100, 50, 20, 10
counts_exclude_gateway: true
growth_already_included: true
allocation: smallest fitting conventional subnet, largest first, lowest aligned address, no gaps
zone_gateways: first usable address
reserve: list remaining CIDRs in ascending order
application: 10.42.0.200
staff_application_service: TCP destination port 443
inter_zone_path: mandatory stateful firewall; VLANs alone do not authorize flows

Checks the server runs (7)

  • Assigned block is preserved
  • Staff capacity and endpoints are exact
  • Guest allocation is aligned and exact
  • Server allocation excludes special addresses
  • Management allocation is minimal
  • Both unused ranges remain reserved
  • Application tuple and enforced routing are explicit

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

    Anchor the plan

    Copy the assigned parent block without enlarging it. Derive the largest zone from its required usable count and distinguish gateway from broadcast.

    Assigned block is preservedStaff capacity and endpoints are exact

  2. Step 2

    Advance through aligned boundaries

    For each remaining zone, find the smallest fitting host field and advance from the previous block end. Use the first host for routing and the final address only for broadcast.

    Guest allocation is aligned and exactServer allocation excludes special addressesManagement allocation is minimal

  3. Step 3

    Account for what is left

    Cover all unused addresses with the requested ordered residual blocks. Do not fold an allocated zone into a reservation.

    Both unused ranges remain reserved

  4. Step 4

    Connect addressing to authorization

    Use the signed application endpoint and service tuple, then explain the mandatory enforcement hop between zones rather than relying on labels.

    Application tuple and enforced routing are explicit

Rules summary

  • XP on pass

    60 bonus XP the first time every check goes green.

  • Paid hints

    2 available. Each costs 25% of the lab XP (about 15 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.