Open the lab
[ YOUR LAB FILE ]
Download the starting topology, then work through the lesson in SwitchLab.
- Save the .swlab file without renaming its extension.
- Open SwitchLab. Import and export controls currently require a desktop-width window. On a smaller screen, Tools → Fit brings the topology into view.
- Select Import Sandbox (folder icon), choose the downloaded file, and confirm the device and cable counts below.
- Select a device, then choose Open device on desktop or its name in the bottom bar on smaller screens. Select CLI for switches/routers or Desktop → Terminal for PCs. Enter
enableonly when the prompt ends in >. - Follow this page beside the simulator. Use a free account to export your work. Reimport the original download to restart; export any work you want to keep first.
Prerequisites
- Complete the focused lessons for the features used in this scenario.
- For campus policy scenarios, complete VLANs, trunks, IPv4, OSPF and ACL lessons first.
Topology
4 devices · 3 links
Scenario
A small office has 25 office hosts and 10 workshop hosts within 172.16.40.0/24. Router interfaces are unaddressed. Complete the subnet plan, local DHCP and routed access to the representative workshop workstation.
Objectives
- Implement or restore the approved network design without breaking required control paths.
- Verify configuration, end-to-end behavior and completed-network persistence.
- Produce an operational handoff with evidence and a deterministic reset path.
CCNA blueprint
200-301 v1.1 objectives — this lab covers the following specific skills, not every subtopic in the domain.
- 1.6 — Apply and verify the scenario’s IPv4 addressing.
- 4.3 — Explain DHCP addressing services.
- 4.6 — Verify a DHCP client lease.
Starting information
- Allocate the lowest /27 for Office on R1 g0/0 and the next /28 for Workshop on g0/1; use each subnet’s first usable address as gateway.
- PC2 is 172.16.40.34/28 with gateway 172.16.40.33. PC1 remains a DHCP client on the Office LAN.
- R1 pool OFFICE serves 172.16.40.0/27; exclude .1–.9 so the isolated PC1 receives .10.
| Host | IPv4 address | Mask | Gateway |
|---|---|---|---|
| PC1 | 255.255.255.224 | None | |
| PC2 | 172.16.40.34 | 255.255.255.240 | 172.16.40.33 |
| Device / port | Device / port |
|---|---|
| PC2 / eth0 | R1 / g0/1 |
| PC1 / eth0 | SW1 / g0/1 |
| SW1 / g0/8 | R1 / g0/0 |
Tasks
- Calculate both subnet boundaries, usable ranges, masks and gateway addresses before configuring the router.
- Configure both gateway interfaces and the Office DHCP pool with its reserved range.
- Renew PC1 and verify its exact lease settings; inspect connected routes and test both inter-LAN directions.
- Save/export/reload and deliver a small-office handoff including the subnet plan, DHCP range and verification evidence.
Useful commands
show ip interface brief
show ip route
copy running-config startup-configProgressive hints
Hint 1
Break the end-to-end path into host settings, local VLAN carriage, gateway reachability, route selection and any access policy.
Hint 2
Use a working control at each layer. Do not remove security controls or add broad routes just to make one ping succeed.
Hint 3
Compare each affected host, interface and route against the approved plan; use the earlier focused lessons for the exact command patterns.
Verification
- The final network matches every approved addressing, VLAN, routing and policy requirement above.
- Every required positive path succeeds and every forbidden path remains blocked.
- Completed export/reload retains the result; reimporting the starter restores the original exercise.
Solution / walkthrough
Show Solution
Use enable only from a > prompt; if already at #, begin with configure terminal.
R1
The /27 uses .0–.31 with usable .1–.30; the /28 uses .32–.47 with usable .33–.46. The router installs both connected routes when its interfaces are addressed and up.
enable
configure terminal
interface g0/0
ip address 172.16.40.1 255.255.255.224
no shutdown
exit
interface g0/1
ip address 172.16.40.33 255.255.255.240
no shutdown
exit
ip dhcp excluded-address 172.16.40.1 172.16.40.9
ip dhcp pool OFFICE
network 172.16.40.0 255.255.255.224
default-router 172.16.40.1
end
copy running-config startup-configPC1
Acquire the first unreserved Office address after the gateway and local DHCP pool are commissioned.
ipconfig /renewRun every verification check above after the changes. A saved configuration alone does not prove packet delivery.