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CCNA lab 2 of 46

IPv4 addressing and VLSM subnetting

Carve one private /22 into right-sized subnets for a dental practice with VLSM, address two routers and three PCs from your own plan, and prove every subnet can reach the others.

Run this lab

It needs Lite: its 5 nodes are set to 5 vCPU and 5,120 MB in total. That fits the free demo too.

In your workspace: Shared, then CCNA 200-301 guided labs, then 02 - IPv4 addressing and VLSM subnetting

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

The free demo needs no card and no email. Every lab plan includes every guided lab.

Level
Beginner
Time
About 55 minutes
Nodes need
5 vCPU, 5,120 MB
Smallest plan
Lite

The scenario

Brightwater Dental has been given the private block 172.16.40.0/22 by its IT partner. The head office router (R1) serves two LANs: Reception (about 100 devices) and Surgery (about 50 devices). A small branch router (R2) serves the Branch LAN (about 20 devices). The two routers are joined by a point-to-point WAN link.

The routers are cabled but nothing is addressed. Your job is to design a subnet plan that wastes as little space as possible, apply it, and prove that every LAN can reach every other LAN.

DeviceInterfaceConnects toAddress (you work it out)
R1Gi0/1PC1 (Reception)first usable of the Reception subnet
R1Gi0/2PC2 (Surgery)first usable of the Surgery subnet
R1Gi0/0R2 Gi0/0 (WAN)first usable of the WAN subnet
R2Gi0/0R1 Gi0/0 (WAN)second usable of the WAN subnet
R2Gi0/1PC3 (Branch)first usable of the Branch subnet
PC1, PC2, PC3eth0their routerlast usable address of their subnet

Topology: PC1 — R1 Gi0/1 · PC2 — R1 Gi0/2 · R1 Gi0/0 — R2 Gi0/0 · R2 Gi0/1 — PC3.

What you’ll practise

  • Work out the prefix length, block size and usable range a subnet needs from a host count
  • Allocate subnets largest first with VLSM and spot boundary-alignment mistakes
  • Address router interfaces and hosts with first and last usable addresses
  • Explain RFC 1918 private addressing and why it needs NAT to reach the Internet
  • Add static and default routes so every subnet is reachable

The tasks

  1. Design the VLSM plan on paper
  2. Address and enable R1
  3. Address and enable R2
  4. Address the PCs
  5. Route between the sites
  6. Private addressing and the Internet
  7. Plan for growth

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.R1R2PC1PC2PC3Gi0/2eth0Gi0/1eth0Gi0/1eth0Gi0/0Gi0/0
5 nodes, with the interface names each link uses. On a narrow screen, scroll the diagram sideways.
Every link, as text
  • R1 Gi0/0 to R2 Gi0/0
  • R1 Gi0/1 to PC1 eth0
  • R1 Gi0/2 to PC2 eth0
  • R2 Gi0/1 to PC3 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
R1Cisco IOSvvios-adventerprisek9-m.SPA.159-3.M61 vCPU, 1,024 MB
R2Cisco IOSvvios-adventerprisek9-m.SPA.159-3.M61 vCPU, 1,024 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
PC3VPCS hostBuilt in to EVE-NGCounted as 1 vCPU, 1,024 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 CCNA 200-301 guided labs.

  3. Open 02 - 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 Cisco. The lab follows exam topics and isn’t vendor training material; vendor names identify the exams and the images in the workspace.