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Fix the VLANs 18 — Library cannot see Library
Enterprise Intermediate 5 devices 4 checked tasks 100 points Plan lab
Scenario — the Library team in Agra rang the help desk: the two Library PCs cannot ping each other, and a new desk in Support has no link at all. The switch was set up last month from a wrong sheet. Port Fa0/2 (a Library desk) was put in the Support VLAN, and Fa0/3 (the new Support desk) was shut down. Find both, fix them and prove each department can talk 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
the Library team in Agra rang the help desk: the two Library PCs cannot ping each other, and a new desk in Support has no link at all. The switch was set up last month from a wrong sheet. Port Fa0/2 (a Library desk) was put in the Support VLAN, and Fa0/3 (the new Support desk) was shut down. Find both, fix them and prove each department can talk again.
Your role: a network engineer on the enterprise team. Level: Intermediate Done when: all 4 goals show as passed (100 points).
Network status
Devices: 1 switch, 4 PCs, cabled as drawn. No Layer 1 or Layer 2 faults: every link is connected and up. SW-Agra starts with and VLAN 44, VLAN 45 already configured. Library-1 is a host with 192.168.37.11/24. Library-2 is a host with 192.168.37.12/24. Support-1 is a host with 192.168.137.21/24. Support-2 is a host with 192.168.137.22/24. Known problems
The network worked and now does not: the scenario above says what users report. The cause is a configuration fault, not a cable. Find it with show commands (interfaces, routes, neighbours, running-config) before you change anything; fix only what is wrong. Goals
Fa0/2 is back in VLAN 44 (Library) (30 pts) Fa0/3 is enabled again (25 pts) The two Library PCs reach each other (25 pts) The two Support PCs reach each other (20 pts) The activity, in order
Fa0/2 is back in VLAN 44 (Library) Why: A VLAN is a separate broadcast domain; the port’s VLAN decides which devices can talk without a router. Verify with: show vlan brief Fa0/3 is enabled again Why: An administratively down port forwards nothing, and a routing protocol cannot form a neighbour over it. Verify with: show ip interface brief The two Library PCs reach each other Why: A ping needs a route in BOTH directions. This is the end-to-end proof that everything before it worked. Verify with: ping 192.168.37.12 The two Support PCs reach each other Why: A ping needs a route in BOTH directions. This is the end-to-end proof that everything before it worked. Verify with: ping 192.168.137.22 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: Fixing the VLAN but leaving the port shut Common mistake: Assigning the port to the right VLAN number on the wrong port Common mistake: Not retesting the other department Why this matters
Most "the network is down" tickets at the access layer are a port in the wrong VLAN or a port that is administratively down. show vlan brief and show interfaces status find both in seconds.
What you will be able to do
Read show vlan brief to find a misplaced port
Spot an administratively-down port
Verify the fix from the end hosts
The network
Catalyst 2960-24TT, PC — 5 devices in all, already cabled.
Fa0/1 Fa0 Fa0/2 Fa0 Fa0/3 Fa0 Fa0/4 Fa0 SW-Agra Library-1 192.168.37.11/24 Library-2 192.168.37.12/24 Support-1 192.168.137.21/24 Support-2 192.168.137.22/24 Drawn from this lab: devices, cables, ports and the addresses already set. Device Model Address already set
SW-Agra Catalyst 2960-24TT configure it Library-1 PC 192.168.37.11 / 255.255.255.0 Library-2 PC 192.168.37.12 / 255.255.255.0 Support-1 PC 192.168.137.21 / 255.255.255.0 Support-2 PC 192.168.137.22 / 255.255.255.0
Cabling
SW-Agra Fa0/1 ↔ Library-1 Fa0 SW-Agra Fa0/2 ↔ Library-2 Fa0 SW-Agra Fa0/3 ↔ Support-1 Fa0 SW-Agra Fa0/4 ↔ Support-2 Fa0
What is configured at the start
These are already configured when the lab opens — including, where this is a troubleshooting lab, the fault itself:
SW-Agra vlan 44
name LIBRARY
exit
vlan 45
name SUPPORT
exit
interface fa0/2
switchport mode access
switchport access vlan 45
exit
interface fa0/1
switchport mode access
switchport access vlan 44
exit
interface fa0/3
switchport mode access
switchport access vlan 45
shutdown
exit
interface fa0/4
switchport mode access
switchport access vlan 45
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 Fa0/2 is back in VLAN 44 (Library) 30 On SW-Agra: show vlan brief — Fa0/2 is an access port in VLAN 44. 2 Fa0/3 is enabled again 25 On SW-Agra: show ip interface brief — Fa0/3 is up/up. 3 The two Library PCs reach each other 25 On Library-1: ping 192.168.37.12 must succeed. 4 The two Support PCs reach each other 20 On Support-1: ping 192.168.137.22 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
Fixing the VLAN but leaving the port shut
Assigning the port to the right VLAN number on the wrong port
Not retesting the other department
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:
SW-Agra interface fa0/2
switchport access vlan 44
exit
interface fa0/3
no shutdown
exit Where this is examined
CCNA 2.0 troubleshooting VLANs; Network+ 5.3.
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