Open the lab

[ YOUR LAB FILE ]

Download the starting topology, then work through the lesson in SwitchLab.

Download SwitchLab Lab (.swlab)

  1. Save the .swlab file without renaming its extension.
  2. Open SwitchLab. Import and export controls currently require a desktop-width window. On a smaller screen, Tools → Fit brings the topology into view.
  3. Select Import Sandbox (folder icon), choose the downloaded file, and confirm the device and cable counts below.
  4. 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 enable only when the prompt ends in >.
  5. 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

  • Understand IPv4 /24 LANs and a /30 transit subnet.
  • Read interface addressing and recognize privileged EXEC and configuration modes.

Follow the CCNA study path · Browse all SwitchLab labs

Topology

Configure Your First IPv4 Static Routes: actual imported SwitchLab starting topology.
Starting topology captured in SwitchLab. Select the image to view it at full size.

4 devices · 3 links

Scenario

A small branch is joining HQ over an already addressed Ethernet transit link. Each site can reach its own gateway, but the routers have no instructions for the other site’s LAN. Install one specific route on each router and follow a packet and its reply through the resulting tables.

Objectives

  • Identify the destination prefix and adjacent next hop for each direction.
  • Install specific static routes on both routers.
  • Distinguish an installed S route from a connected route and prove two-way delivery.

CCNA blueprint

200-301 v1.1 objectives — this lab covers the following specific skills, not every subtopic in the domain.

  • 3.1.a — Identify a static route in the IPv4 routing table.
  • 3.1.d — Verify the next-hop address.
  • 3.3.b — Configure and verify IPv4 network routes and the return path.

Starting information

  • All physical interfaces and PC addresses are correct. Neither router has a static or dynamic route to the remote LAN.
  • R1 is attached to 10.10.10.0/24 and R2 to 10.20.20.0/24. Their transit addresses are 10.0.12.1 and 10.0.12.2.
  • Use specific /24 static routes in both directions. This introduction does not use default routes.
HostIPv4 addressMaskGateway
PC110.10.10.10255.255.255.010.10.10.1
PC210.20.20.20255.255.255.010.20.20.1
RouterInterfaceIPv4 addressMask
R1g0/010.10.10.1255.255.255.0
R1g0/110.0.12.1255.255.255.252
R2g0/010.20.20.1255.255.255.0
R2g0/110.0.12.2255.255.255.252
Device / portDevice / port
PC1 / eth0R1 / g0/0
R1 / g0/1R2 / g0/1
PC2 / eth0R2 / g0/0

Tasks

  1. Ping each local gateway and try the remote workstation. Compare the connected prefixes in show ip route with the destination you cannot reach.
  2. On R1 enter configure terminal, then ip route 10.20.20.0 255.255.255.0 10.0.12.2, and end. The destination is the remote LAN; the next hop is the adjacent router, not the remote PC.
  3. On R2 use the same command pattern for 10.10.10.0/24 through R1’s transit address. Explain why R1’s new route alone cannot carry the reply.
  4. Find the S-coded remote /24 on each router. Test PC1 to PC2 and PC2 to PC1, then save both router configurations.

Useful commands

show ip interface brief
show ip route
show running-config
ping 10.0.12.2
ip route <network> <mask> <next-hop>
copy running-config startup-config

Progressive hints

Hint 1

A router already knows its connected subnets. Which remote LAN is missing from each table?

Hint 2

The next hop is a router on a connected transit subnet. It is not the destination host address.

Hint 3

R1 forwards the branch /24 through 10.0.12.2. R2 needs the reciprocal HQ /24 route through 10.0.12.1.

Verification

  • Both local gateways work before and after configuration. Initially remote PC traffic fails.
  • R1 installs S 10.20.20.0/24 through 10.0.12.2; R2 installs S 10.10.10.0/24 through 10.0.12.1.
  • Both routes use the default static administrative distance of 1. No default route is required.
  • PC1 → 10.20.20.20 and PC2 → 10.10.10.10 succeed.

Solution / walkthrough

Show Solution

Use enable only from a > prompt; if already at #, begin with configure terminal.

R1

Send branch-bound traffic to the adjacent branch router.

enable
configure terminal
ip route 10.20.20.0 255.255.255.0 10.0.12.2
end
copy running-config startup-config

R2

Provide the reciprocal HQ route so replies have a valid forwarding path.

enable
configure terminal
ip route 10.10.10.0 255.255.255.0 10.0.12.1
end
copy running-config startup-config

Run every verification check above after the changes. A saved configuration alone does not prove packet delivery.

Previous lab

Repair an Incorrect Default Gateway

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