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Junction with a tail 52 — RIP repair
Enterprise Intermediate 8 devices 5 checked tasks 61 points Plan lab
Scenario — Indore is a junction with no LAN: Meerut, Hubli and the Aizawl–Puducherry tail all meet there. Everything was configured last week and the network worked. Today the end offices cannot reach each other: one router is not advertising the network of one of its links. 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
Indore is a junction with no LAN: Meerut, Hubli and the Aizawl–Puducherry tail all meet there. Everything was configured last week and the network worked. Today the end offices cannot reach each other: one router is not advertising the network of one of its links. 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 5 goals show as passed (61 points).
Network status
Devices: 5 routers, 3 PCs, cabled as drawn. No Layer 1 or Layer 2 faults: every link is connected and up. R-Meerut starts with addresses (G0/0 10.71.1.1/24, G0/1 172.19.51.1/30) and RIP already configured. PC-Meerut is a host with 10.71.1.10/24, gateway 10.71.1.1. R-Indore starts with addresses (G0/0 172.19.51.2/30, G0/1 172.19.51.5/30, G0/2 172.19.51.9/30) and RIP already configured. R-Hubli starts with addresses (G0/0 10.71.2.1/24, G0/1 172.19.51.6/30) and RIP already configured. PC-Hubli is a host with 10.71.2.10/24, gateway 10.71.2.1. R-Aizawl starts with addresses (G0/0 172.19.51.10/30, G0/1 172.19.51.13/30) and RIP already configured. R-Puducherry starts with addresses (G0/0 10.71.3.1/24, G0/1 172.19.51.14/30) and RIP already configured. PC-Puducherry is a host with 10.71.3.10/24, gateway 10.71.3.1. Known problems
Routers beside R-Hubli never learn its link network, so routes through it are missing. 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
The router that was silent now advertises its link network too (15 pts) R-Meerut learns 10.71.3.0/24 from the protocol (10 pts) 10.71.1.10 (Meerut) reaches 10.71.3.10 (Puducherry) (12 pts) 10.71.2.10 (Hubli) reaches 10.71.1.10 (Meerut) (12 pts) Every LAN reaches every other LAN (12 pts) The activity, in order
Confirm the symptom: ping the far PC from the near PC and note where it fails. Why: This is the task that checks your configuration directly: the line must really be there, not just look right. Verify with: show running-config Follow the path hop by hop. On each router read its neighbours and its routes, starting with the one nearest the failure. Why: If the prefix is not in the routing table, the router drops packets for it, whatever else is configured. Verify with: show ip route 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 10.71.3.10 Fix the single wrong line and nothing else. Why: A ping needs a route in BOTH directions. This is the end-to-end proof that everything before it worked. Verify with: ping 10.71.1.10 Retest: neighbours, routes, then pings in both directions. Why: A ping needs a route in BOTH directions. This is the end-to-end proof that everything before it worked. Verify with: ping 10.71.2.10 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: Staying on version 1 (no masks) Common mistake: Forgetting no auto-summary Common mistake: Advertising only one of the classful networks in use Why this matters
RIP counts hops and repeats its whole table every thirty seconds. It is simple and old, and still examined because it shows distance-vector behaviour in its plainest form; version 2 carries masks, version 1 does not.
What you will be able to do
Enable RIPv2 with classful network statements
Turn off automatic summarisation
Spot a link network that is not advertised
The network
ISR 2911, PC — 8 devices in all, already cabled.
Fa0 Gi0/0 10.71.1.1/24 Fa0 Gi0/0 10.71.2.1/24 Fa0 Gi0/0 10.71.3.1/24 Gi0/1 172.19.51.1/30 Gi0/0 172.19.51.2/30 Gi0/1 172.19.51.5/30 Gi0/1 172.19.51.6/30 Gi0/2 172.19.51.9/30 Gi0/0 172.19.51.10/30 Gi0/1 172.19.51.13/30 Gi0/1 172.19.51.14/30 R-Meerut PC-Meerut 10.71.1.10/24 · gw 10.71.1.1 R-Indore R-Hubli PC-Hubli 10.71.2.10/24 · gw 10.71.2.1 R-Aizawl R-Puducherry PC-Puducherry 10.71.3.10/24 · gw 10.71.3.1 Drawn from this lab: devices, cables, ports and the addresses already set. Device Model Address already set
R-Meerut ISR 2911 configure it PC-Meerut PC 10.71.1.10 / 255.255.255.0 gw 10.71.1.1 R-Indore ISR 2911 configure it R-Hubli ISR 2911 configure it PC-Hubli PC 10.71.2.10 / 255.255.255.0 gw 10.71.2.1 R-Aizawl ISR 2911 configure it R-Puducherry ISR 2911 configure it PC-Puducherry PC 10.71.3.10 / 255.255.255.0 gw 10.71.3.1
Cabling
PC-Meerut Fa0 ↔ R-Meerut Gi0/0 PC-Hubli Fa0 ↔ R-Hubli Gi0/0 PC-Puducherry Fa0 ↔ R-Puducherry Gi0/0 R-Meerut Gi0/1 ↔ R-Indore Gi0/0 R-Indore Gi0/1 ↔ R-Hubli Gi0/1 R-Indore Gi0/2 ↔ R-Aizawl Gi0/0 R-Aizawl Gi0/1 ↔ R-Puducherry 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-Meerut interface g0/0
ip address 10.71.1.1 255.255.255.0
no shutdown
exit
interface g0/1
ip address 172.19.51.1 255.255.255.252
no shutdown
exit
router rip
version 2
no auto-summary
network 10.0.0.0
network 172.19.0.0
passive-interface GigabitEthernet0/0
exit R-Indore interface g0/0
ip address 172.19.51.2 255.255.255.252
no shutdown
exit
interface g0/1
ip address 172.19.51.5 255.255.255.252
no shutdown
exit
interface g0/2
ip address 172.19.51.9 255.255.255.252
no shutdown
exit
router rip
version 2
no auto-summary
network 10.0.0.0
network 172.19.0.0
exit R-Hubli interface g0/0
ip address 10.71.2.1 255.255.255.0
no shutdown
exit
interface g0/1
ip address 172.19.51.6 255.255.255.252
no shutdown
exit
router rip
version 2
no auto-summary
network 10.0.0.0
passive-interface GigabitEthernet0/0
exit R-Aizawl interface g0/0
ip address 172.19.51.10 255.255.255.252
no shutdown
exit
interface g0/1
ip address 172.19.51.13 255.255.255.252
no shutdown
exit
router rip
version 2
no auto-summary
network 10.0.0.0
network 172.19.0.0
exit R-Puducherry interface g0/0
ip address 10.71.3.1 255.255.255.0
no shutdown
exit
interface g0/1
ip address 172.19.51.14 255.255.255.252
no shutdown
exit
router rip
version 2
no auto-summary
network 10.0.0.0
network 172.19.0.0
passive-interface GigabitEthernet0/0
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 The router that was silent now advertises its link network too 15 On R-Hubli: show running-config contains the line(s) matching network 172\.19\.0\.0. 2 R-Meerut learns 10.71.3.0/24 from the protocol 10 On R-Meerut: show ip route lists 10.71.3.0/24. 3 10.71.1.10 (Meerut) reaches 10.71.3.10 (Puducherry) 12 On PC-Meerut: ping 10.71.3.10 must succeed. 4 10.71.2.10 (Hubli) reaches 10.71.1.10 (Meerut) 12 On PC-Hubli: ping 10.71.1.10 must succeed. 5 Every LAN reaches every other LAN 12 On PC-Meerut: ping 10.71.2.10 must succeed. and On PC-Meerut: ping 10.71.3.10 must succeed. and On PC-Hubli: ping 10.71.1.10 must succeed. and On PC-Hubli: ping 10.71.3.10 must succeed. and On PC-Puducherry: ping 10.71.1.10 must succeed. and On PC-Puducherry: ping 10.71.2.10 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
Staying on version 1 (no masks)
Forgetting no auto-summary
Advertising only one of the classful networks in use
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-Hubli router rip
network 172.19.0.0
exit Where this is examined
CCNA 3.0 routing fundamentals; Network+ 2.1 dynamic routing.
This lab practises these topics in the zNetLaB certification courses:
Related labs
Where to start
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