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Two-site 12 — static routes repair
Enterprise Intermediate 4 devices 3 checked tasks 48 points Plan lab
Scenario — Kochi and Gurugram are two offices joined by a single leased line. Everything was configured last week and the network worked. Today the end offices cannot reach each other: one router has lost a route, so packets go out but the replies never come back. Find it, fix it and prove the end-to-end paths again. You build it in a browser, type real commands at each device, and every task below is
checked against the running configuration — so you find out it is wrong before anybody else does.
Open this lab in the simulator
The simulator runs in your browser with nothing to install. This lab is part of the full simulator: open it free for 7 days with a new account, then with a plan. It needs an account, which keeps your progress.
The scenario
Kochi and Gurugram are two offices joined by a single leased line. Everything was configured last week and the network worked. Today the end offices cannot reach each other: one router has lost a route, so packets go out but the replies never come back. Find it, fix it and prove the end-to-end paths again.
Your role: a network engineer on the enterprise team. Level: Intermediate Done when: all 3 goals show as passed (48 points).
Network status
Devices: 2 routers, 2 PCs, cabled as drawn. No Layer 1 or Layer 2 faults: every link is connected and up. R-Kochi starts with addresses (G0/0 10.31.1.1/24, G0/1 172.27.11.1/30) and static routes already configured. PC-Kochi is a host with 10.31.1.10/24, gateway 10.31.1.1. R-Gurugram starts with addresses (G0/0 10.31.2.1/24, G0/1 172.27.11.2/30). PC-Gurugram is a host with 10.31.2.10/24, gateway 10.31.2.1. Known problems
A ping from 10.31.1.10 to 10.31.2.10 times out although every link is up. No cable or interface is faulty: the fault is one line of configuration on one router. Everything else is correct and must be left alone. Goals
R-Gurugram: a route — 10.31.1.0/24 via 172.27.11.1 (8 pts) 10.31.1.10 (Kochi) reaches 10.31.2.10 (Gurugram) (20 pts) 10.31.2.10 (Gurugram) reaches 10.31.1.10 (Kochi) (20 pts) The activity, in order
Confirm the symptom: ping the far PC from the near PC and note where it fails. Why: The next hop must be an address on a directly connected subnet, or the route never enters the table. Verify with: show ip route Follow the path hop by hop. On each router read its neighbours and its routes, starting with the one nearest the failure. Why: A ping needs a route in BOTH directions. This is the end-to-end proof that everything before it worked. Verify with: ping 10.31.2.10 Compare the suspect router with its neighbour: the same protocol, the same numbers, every link covered. Why: A ping needs a route in BOTH directions. This is the end-to-end proof that everything before it worked. Verify with: ping 10.31.1.10 Fix the single wrong line and nothing else. Check: show running-config Retest: neighbours, routes, then pings in both directions. Check: show ip route static, then ping Tips
Work in the order given: later goals depend on the earlier ones. After every change, run the verify command before moving on; do not guess. Stuck? Read the verify output first. It names the interface, neighbour or route that is wrong. Common mistake: Adding the route only one way — the ping leaves and never returns Common mistake: Using the far router’s address instead of the directly connected neighbour as next hop Common mistake: Forgetting a transit router in the middle of the chain Why this matters
A router only knows its connected networks. With static routes you write every other network in by hand — one next hop per destination — and the same must be done in the opposite direction or the reply is lost.
What you will be able to do
Work out the next hop toward each remote LAN from a diagram
Write ip route statements with the right prefix, mask and next hop
Explain why every router on the path needs the route
The network
ISR 2911, PC — 4 devices in all, already cabled.
Fa0 Gi0/0 10.31.1.1/24 Fa0 Gi0/0 10.31.2.1/24 Gi0/1 172.27.11.1/30 Gi0/1 172.27.11.2/30 R-Kochi PC-Kochi 10.31.1.10/24 · gw 10.31.1.1 R-Gurugram PC-Gurugram 10.31.2.10/24 · gw 10.31.2.1 Drawn from this lab: devices, cables, ports and the addresses already set. Device Model Address already set
R-Kochi ISR 2911 configure it PC-Kochi PC 10.31.1.10 / 255.255.255.0 gw 10.31.1.1 R-Gurugram ISR 2911 configure it PC-Gurugram PC 10.31.2.10 / 255.255.255.0 gw 10.31.2.1
Cabling
PC-Kochi Fa0 ↔ R-Kochi Gi0/0 PC-Gurugram Fa0 ↔ R-Gurugram Gi0/0 R-Kochi Gi0/1 ↔ R-Gurugram Gi0/1
What is configured at the start
These are already configured when the lab opens — including, where this is a troubleshooting lab, the fault itself:
R-Kochi interface g0/0
ip address 10.31.1.1 255.255.255.0
no shutdown
exit
interface g0/1
ip address 172.27.11.1 255.255.255.252
no shutdown
exit
ip route 10.31.2.0 255.255.255.0 172.27.11.2 R-Gurugram interface g0/0
ip address 10.31.2.1 255.255.255.0
no shutdown
exit
interface g0/1
ip address 172.27.11.2 255.255.255.252
no shutdown
exit Tasks, and how each one is checked
Every task is decided by reading the live network — a neighbour in FULL, a ping that succeeds, a line in the running configuration — not by looking for a keyword you typed. The same command shows you what the lab sees.
# Task Pts How to verify it yourself
1 R-Gurugram: a route — 10.31.1.0/24 via 172.27.11.1 8 On R-Gurugram: show ip route 10.31.1.0 shows next hop 172.27.11.1. 2 10.31.1.10 (Kochi) reaches 10.31.2.10 (Gurugram) 20 On PC-Kochi: ping 10.31.2.10 must succeed. 3 10.31.2.10 (Gurugram) reaches 10.31.1.10 (Kochi) 20 On PC-Gurugram: ping 10.31.1.10 must succeed.
Stuck? Ask the coach
Tell the coach what you see or what you tried. It gives you a hint, not the answer, the way a senior engineer would. Included with a free trial or any plan.
Ask the coach
Common mistakes
Adding the route only one way — the ping leaves and never returns
Using the far router’s address instead of the directly connected neighbour as next hop
Forgetting a transit router in the middle of the chain
Reference solution
Try it yourself first — the lab checks your work either way. This is one configuration that makes every task pass, device by device:
R-Gurugram ip route 10.31.1.0 255.255.255.0 172.27.11.1 Where this is examined
CCNA 3.0 static routing; Network+ 2.1 routing technologies.
This lab practises these topics in the zNetLaB certification courses:
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