Find three planted faults, layer by layer, with show commands, ping and traceroute

Steps

1. Place the devices and cable them as the Links table lists. Use Copper Straight-Through for PC1 to S1 and S1 to R1, and Copper Cross-Over for R1 to R2 and R2 to PC2 (or let Packet Tracer's automatic connection type choose). When a router first boots, Packet Tracer asks Would you like to enter the initial configuration dialog? [yes/no]:. Answer no and press Enter to reach the Router> prompt. Give PC1 and PC2 their addresses and gateways from the Addressing table.
2. On S1, put PC1's port and the router's port in VLAN 10:

Switch> enable
Switch# configure terminal
Switch(config)# hostname S1
S1(config)# vlan 10
S1(config-vlan)# name USERS
S1(config-vlan)# exit
S1(config)# interface FastEthernet0/1
S1(config-if)# switchport mode access
S1(config-if)# switchport access vlan 10
S1(config-if)# exit
S1(config)# interface GigabitEthernet0/1
S1(config-if)# switchport mode access
S1(config-if)# switchport access vlan 10
S1(config-if)# end

3. Address both routers. R1 sends everything it has no route for to R2 with a default route, the S* entry from lesson 11's route table. R2 is deliberately given no route back to 192.168.1.0/24: that omission is the third fault, so do not add one yet.

Router> enable
Router# configure terminal
Router(config)# hostname R1
R1(config)# interface GigabitEthernet0/0/0
R1(config-if)# ip address 192.168.1.1 255.255.255.0
R1(config-if)# no shutdown
R1(config-if)# interface GigabitEthernet0/0/1
R1(config-if)# ip address 10.0.12.1 255.255.255.252
R1(config-if)# no shutdown
R1(config-if)# exit
R1(config)# ip route 0.0.0.0 0.0.0.0 10.0.12.2
R1(config)# end
Router> enable
Router# configure terminal
Router(config)# hostname R2
R2(config)# interface GigabitEthernet0/0/0
R2(config-if)# ip address 192.168.2.1 255.255.255.0
R2(config-if)# no shutdown
R2(config-if)# interface GigabitEthernet0/0/1
R2(config-if)# ip address 10.0.12.2 255.255.255.252
R2(config-if)# no shutdown
R2(config-if)# end

Take a baseline on R1 with show ip interface brief (both interfaces up and up) and ping 10.0.12.2. A first result of .!!!! is normal: the first echo was dropped while R1 resolved ARP for R2. 4. Fault 1, Layer 2. Plant it on S1:

S1# configure terminal
S1(config)# interface FastEthernet0/1
S1(config-if)# switchport access vlan 20
S1(config-if)# end

The switch creates VLAN 20 on the spot, so there is no error. From PC1, run ping 192.168.1.1 and expect Request timed out. four times. Work up from the bottom. On S1, show ip interface brief would show Fa0/1 up, so Layer 1 is fine. Then run show vlan brief: Fa0/1 sits under VLAN 20 while Gi0/1, the router's port, sits under VLAN 10. Then run show mac address-table and find PC1's MAC address learned on Fa0/1 in VLAN 20. PC1's ARP requests for its gateway never reach VLAN 10. Fix it with switchport access vlan 10 on Fa0/1 and repeat the ping until it replies. 5. Fault 2, Layer 1 seen from the far end. On R2, shut the link toward R1:

R2# configure terminal
R2(config)# interface GigabitEthernet0/0/1
R2(config-if)# shutdown
R2(config-if)# end

On R1, run show ip interface brief. R1's own G0/0/1 now reads down and down: a Layer 1 state, because the far end is shut. Only R2 shows administratively down for its G0/0/1. Run show ip route on R1 as well: the connected 10.0.12.0/30 route has gone, and the default route has gone with it, because its next hop is no longer reachable. Read the log lines on R1's console too: a %LINK line and a %LINEPROTO-5-UPDOWN line for GigabitEthernet0/0/1, changed state to down. Fix it with no shutdown on R2's G0/0/1 and confirm both ends return to up and up. 6. Fault 3, Layer 3. From PC1, run ping 192.168.2.10 and expect Request timed out. Then trace the path:

C:\> tracert 192.168.2.10

Hop 1, 192.168.1.1, answers and the following hops time out (let it run, or close and reopen the Command Prompt to stop it). Replies stop after R1, so look at R1 and the device beyond it. On R1, a standard ping 192.168.2.10 succeeds, because R1 sources it from 10.0.12.1, an address R2 is directly connected to. Now test the path the users take, with an extended ping sourced from R1's LAN address. Press Enter to accept the default at every line except the three shown with a value:

R1# ping
Protocol [ip]:
Target IP address: 192.168.2.10
Repeat count [5]:
Datagram size [100]:
Timeout in seconds [2]:
Extended commands [n]: y
Source address or interface: 192.168.1.1

Keep pressing Enter through the remaining questions. The result is five dots and Success rate is 0 percent (0/5): replies to 192.168.1.0/24 have no way home. Confirm it on R2 with show ip route, which lists no entry covering 192.168.1.1 and says Gateway of last resort is not set, so R2 drops the replies. 7. Fix the return path on R2:

R2# configure terminal
R2(config)# ip route 192.168.1.0 255.255.255.0 10.0.12.1
R2(config)# end

Repeat the extended ping from R1, sourced from 192.168.1.1, and expect !!!!!. Then repeat PC1's ping and traceroute to 192.168.2.10. 8. Write your fault log: for each of the three faults, the symptom the user would report, the first command whose output located it, the exact line that gave it away, and the fix. Add one line on why the standard ping from R1 passed while users still failed.