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Network+ lab 3 of 27

IPv4 addressing and VLSM subnetting

Carve one /23 into right-sized subnets with VLSM, configure a router and three hosts from your own plan, and fix a head-office route by summarising the block with CIDR. You check your maths with ipcalc and classify addresses the way the exam asks.

Run this lab

It needs Lite: its 5 nodes are set to 5 vCPU and 3,584 MB in total. That fits the free demo too.

In your workspace: Shared, then CompTIA Network Plus N10-009 guided labs, then 03 - IPv4 addressing and VLSM subnetting

Try it free for 30 minutesRun it on Lite from £3 a day

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Level
Beginner
Time
About 60 minutes
Nodes need
5 vCPU, 3,584 MB
Smallest plan
Lite

The scenario

Harbour Logistics is opening a new depot. Head office has given it 172.16.40.0/23 and nothing else. You must split the block into subnets that fit each group with minimal waste, then configure the depot router R1 and three test hosts from your plan. Head office's router R2 is already connected, but whoever set it up only routed part of the depot block back.

SegmentHosts neededDeviceR1 interface
Warehouse200PC1Gi0/0
Office100PC2Gi0/1
Guest Wi-Fi (not built yet)50R1 Loopback1 as a placeholderLoopback1
Management25H1 (Linux)Gi0/2
Link to HQ2R2 Gi0/0 is 172.16.41.226Gi0/3

Rules for this lab (so everyone gets the same answer): allocate the largest subnet first, starting at 172.16.40.0, each new subnet at the next free address. R1 always takes the first usable address; the test host takes the last usable address.

What you’ll practise

  • Size subnets with VLSM from host counts, largest first
  • Work out network, first and last usable, and broadcast addresses for any prefix
  • Configure router interfaces and Linux and PC hosts from an addressing plan
  • Summarise contiguous subnets into one CIDR route
  • Classify private, public, loopback, APIPA and class A to E addresses

The tasks

  1. Plan the subnets with VLSM
  2. Address the router
  3. Address the hosts
  4. Route to head office and fix the summary
  5. Classify addresses like the exam does

The Lab Tasks pane has the scenario, these tasks, the checks to run, hints and the full solution.

Topology and devices

The network as it opens in EVE-NG, drawn from the lab’s own canvas, and the image each node runs.

Topology of IPv4 addressing and VLSM subnetting5 nodes, 4 links. Every link is listed as text below the diagram.R2R1PC1PC2H1Gi0/0Gi0/3Gi0/0eth0Gi0/2eth0Gi0/1eth0
5 nodes, with the interface names each link uses. On a narrow screen, scroll the diagram sideways.
Every link, as text
  • R2 Gi0/0 to R1 Gi0/3
  • R1 Gi0/0 to PC1 eth0
  • R1 Gi0/1 to PC2 eth0
  • R1 Gi0/2 to H1 eth0
Nodes in IPv4 addressing and VLSM subnetting, with the image each runs and the vCPU and RAM it’s set to
NodeDeviceImage in Add NodeSet to
R2Cisco IOSvvios-adventerprisek9-m.SPA.159-3.M61 vCPU, 512 MB
R1Cisco IOSvvios-adventerprisek9-m.SPA.159-3.M61 vCPU, 512 MB
PC1VPCS hostBuilt in to EVE-NGCounted as 1 vCPU, 1,024 MB
PC2VPCS hostBuilt in to EVE-NGCounted as 1 vCPU, 1,024 MB
H1Alpine Linuxclbalpinebase-alpine-base-3-20-31 vCPU, 512 MB

How to open this lab

  1. Sign in to your workspace at lab.cloudlabbox.com.

  2. In File Manager, open Shared, then the folder CompTIA Network Plus N10-009 guided labs.

  3. Open 03 - IPv4 addressing and VLSM subnetting and start its nodes, then open Lab Tasks for the scenario and the steps.

The lab is read-only. You can start the nodes and configure the devices, but changes to the topology can’t be saved. To change it, rebuild it in your own folder.

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CloudLabBox is independent of CompTIA, Cisco and Netgate. The lab follows exam topics and isn’t vendor training material; vendor names identify the exams and the images in the workspace.