Same for:
- 1.5.6 Packet Tracer - Troubleshooting Challenge - Use Documentation to Solve Issues
- 37.5.6 Packet Tracer - Troubleshooting Challenge - Use Documentation to Solve Issues
12.6.2 Packet Tracer - Troubleshooting Challenge - Use Documentation to Solve Issues Answers
Topology
12.6.2 Packet Tracer - Troubleshooting Challenge - Use Documentation to Solve Issues
Addressing Table
| Device | Interface | Device Type (router, switch, host) |
IP Address | Subnet Mask | Default Gateway |
|---|---|---|---|---|---|
| PC1 | NIC | host | 192.168.1.153 | 255.255.255.0 | 192.168.1.1 |
| PC2 | NIC | host | 192.168.3.50 | 255.255.255.0 | 192.168.3.1 |
| PC3 | NIC | host | 192.168.4.115 | 255.255.255.0 | 192.168.4.1 |
| PC4 | NIC | host | 192.168.5.83 | 255.255.255.128 | 192.168.5.1 |
| PC5 | NIC | host | 192.168.5.227 | 255.255.255.128 | 192.168.5.129 |
| PC6 | NIC | host | 192.168.2.48 | 255.255.255.224 | 192.168.2.33 |
| PC7 | NIC | host | 192.168.2.67 | 255.255.255.224 | 192.168.2.65 |
| Hub | G0/0/0 | router | 192.0.2.1 | 255.255.255.252 | N/A |
| Hub | S0/1/0 | router | 192.168.0.1 | 255.255.255.252 | N/A |
| Hub | S0/1/1 | router | 192.168.0.5 | 255.255.255.252 | N/A |
| Hub | S0/2/0 | router | 192.168.0.9 | 255.255.255.252 | N/A |
| Hub | S0/2/1 | router | 192.168.0.13 | 255.255.255.252 | N/A |
| Branch-1 | G0/0/0 | router | 192.168.1.1 | 255.255.255.0 | N/A |
| Branch-1 | S0/1/0 | router | 192.168.0.2 | 255.255.255.252 | N/A |
| Branch-2 | G0/0/0.1 | router | 192.168.2.1 | 255.255.255.224 | N/A |
| Branch-2 | G0/0/0.32 | router | 192.168.2.33 | 255.255.255.224 | N/A |
| Branch-2 | G0/0/0.64 | router | 192.168.2.65 | 255.255.255.224 | N/A |
| Branch-2 | S0/1/0 | router | 192.168.0.6 | 255.255.255.252 | N/A |
| Factory | G0/0/0 | router | 192.168.3.1 | 255.255.255.0 | N/A |
| Factory | G0/0/1 | router | 192.168.4.1 | 255.255.255.0 | N/A |
| Factory | S0/1/0 | router | 192.168.0.14 | 255.255.255.252 | N/A |
| HQ | G0/0/0.1 | router | 192.168.6.1 | 255.255.255.0 | N/A |
| HQ | G0/0/0.5 | router | 192.168.5.1 | 255.255.255.128 | N/A |
| HQ | G0/0/0.10 | router | 192.168.5.129 | 255.255.255.128 | N/A |
| HQ | S0/1/0 | router | 192.168.0.10 | 255.255.255.252 | N/A |
| SW-B1 | VLAN 1 | switch | 192.168.1.252 | 255.255.255.0 | 192.168.1.1 |
| SW-B2 | VLAN 1 | switch | 192.168.2.17 | 255.255.255.224 | 192.168.2.1 |
| SW-F1 | VLAN 1 | switch | 192.168.3.252 | 255.255.255.0 | 192.168.3.1 |
| SW-F2 | VLAN 1 | switch | 192.168.4.252 | 255.255.255.0 | 192.168.4.1 |
| SW-HQ1 | VLAN 1 | switch | 192.168.6.252 | 255.255.255.0 | 192.168.6.1 |
| SW-HQ2 | VLAN 1 | switch | 192.168.6.253 | 255.255.255.0 | 192.168.6.1 |
| SW-HQ3 | VLAN 1 | switch | 192.168.6.254 | 255.255.255.0 | 192.168.6.1 |
| DNS Server | NIC | host (server) | 192.168.5.252 | 255.255.255.128 | 192.168.5.129 |
| ISP | G0/0/0 | router | 192.0.2.2 | 255.255.255.252 | N/A |
| Internet Server | NIC | host (server) | 203.0.113.27 | N/A | N/A |
Objectives
In this lab, you use network documentation to identify and fix network communications problems.
- Use various techniques and tools to identify connectivity issues.
- Use documentation to guide troubleshooting efforts.
- Identify specific network problems.
- Implement solutions to network communication problems.
- Verify network operation.
Background / Scenario
In this activity, you will use the documentation that you created in the Packet Tracer - Troubleshooting Challenge - Document the Network activity to guide network troubleshooting efforts.
It has been discovered that the network that you worked with in the previous PT activity has developed communication problems. Some hosts are unable to ping other hosts and the internet server. It is your job to determine what the issues are and to locate and repair them.
Network issues could exist in any device. Be sure to check for comprehensive errors:
- Addressing configuration
- Interface activation
- Routing
- NAT
Instructions
Passwords for all devices are VTY: cisco, Enable secret: class
Part 1: Assess Connectivity
All hosts should be able to ping each other and the internet server. Determine if this requirement is met. If not, identify which hosts and networks should be further investigated.
What we learned:
- Only PC2 and PC4 can reach the Internet Server. Five PCs have connectivity problems.
- PC3 cannot reach its own gateway, so the problem is in the Factory LAN 192.168.4.0/24 (the gateway interface or the LAN itself).
- PC5 can reach its gateway but not other networks. Its default gateway is 0.0.0.0, so the problem is on the PC itself.
- PC6 and PC7 receive Destination host unreachable from their own gateway. Branch-2 does not have a route to the Internet Server.
- PC1 reaches its gateway, but the ping to the server simply times out. The problem is farther along the path; Part 2 uses tracert to find it.
| PC | Default Gateway | Ping Gateway | Ping Internet Server (203.0.113.27) | Investigate |
|---|---|---|---|---|
| PC1 | 192.168.1.1 | Success | Fail (Request timed out) | Problem 1: path from PC1 to the internet |
| PC2 | 192.168.3.1 | Success | Success | - |
| PC3 | 192.168.4.1 | Fail | Fail | Problem 2 and Problem 3: Factory LAN 192.168.4.0/24 |
| PC4 | 192.168.5.1 | Success | Success | - |
| PC5 | 192.168.5.129 | Success | Fail (also fails to PC4) | Problem 4: PC5 configuration (default gateway 0.0.0.0) |
| PC6 | 192.168.2.33 | Success | Fail (Destination host unreachable from 192.168.2.33) | Problem 5: routing on Branch-2 |
| PC7 | 192.168.2.65 | Success | Fail (Destination host unreachable from 192.168.2.65) | Problem 5: routing on Branch-2 |
Quick Reference: Symptoms, Causes and Fixes
Use this table to jump to the detailed analysis (Problem) or the repair steps (Fix) of each issue.
| # | Symptom | Command that reveals the cause | Cause | Fix |
|---|---|---|---|---|
| 1 | PC1 pings its gateway, but the trace to 203.0.113.27 stops after the Hub (192.168.0.1). | Hub: show ip nat statistics |
Hub S0/1/0 is not a NAT inside interface. | ip nat inside on Hub S0/1/0 |
| 2 | PC3 cannot ping its own gateway 192.168.4.1. | Factory: show ip interface brief |
Factory G0/0/1 is administratively down. | no shutdown on Factory G0/0/1 |
| 3 | After Fix 2, PC3 pings its gateway but still not the server. | Hub: show ip route 192.168.4.0Factory: show running-config | section router ospf |
192.168.4.0/24 is missing from Factory OSPF process 10. | network 192.168.4.0 0.0.0.255 area 0 |
| 4 | PC5 pings its gateway but no other network. | PC5: ipconfig /all |
PC5 default gateway is 0.0.0.0. | Set the gateway to 192.168.5.129 |
| 5 | PC6/PC7 get Destination host unreachable from their gateway. | Branch-2: show ip route, show ip ospf neighbor |
Branch-2 S0/1/0 has the wrong IP 192.168.0.17, so no OSPF adjacency forms. | ip address 192.168.0.6 255.255.255.252 on Branch-2 S0/1/0 |
Part 2: Access Network Devices
From the hosts which have communication problems, use ICMP tools to determine where in the network these problems may be located. From the host PCs, access devices in the network and display configurations and operational status.
Access Map: which PC to use for each device
The routers can be reached only by Telnet from a PC that still has connectivity. All routers use the VTY password cisco and the enable secret class.
| Device to inspect | Start from | Telnet path | Why this PC |
|---|---|---|---|
| Branch-1, then Hub | PC1 | telnet 192.168.1.1 (Branch-1), then telnet 192.168.0.1 (Hub) |
PC1 reaches its gateway, and Branch-1 reaches the nearest Hub interface over S0/1/0. |
| Factory | PC2 | telnet 192.168.3.1 |
PC3 cannot use its own gateway (G0/0/1 is down), but PC2 is on the other Factory LAN, which works. |
| Branch-2 | PC6 (or PC7) | telnet 192.168.2.33 (PC7: 192.168.2.65) |
PC6 reaches its gateway; the fault is on the WAN side of Branch-2. |
| PC5 | PC5 itself | Desktop > IP Configuration | The fault is in the PC settings, not on a network device. |
Note: Fix 5 changes the IP address of Branch-2 S0/1/0. The Telnet session from PC6 is not dropped, because it uses the LAN subinterface G0/0/0.32, not the serial link.
Problem 1: PC1 cannot reach the Internet Server
PC1 can ping its default gateway and some other devices in the network, but it cannot ping Internet Server. Further testing reveals that some other PCs can reach the server. This indicates that the issue is likely related to the path that PC1 is taking to reach the internet. A trace indicates that packets only reach the Hub router.
C:\> tracert 203.0.113.27 Tracing route to 203.0.113.27 over a maximum of 30 hops: 1 0 ms 1 ms 0 ms 192.168.1.1 2 2 ms 2 ms 1 ms 192.168.0.1 3 * * * Request timed out. 4 * * * Request timed out. 5 * * * Request timed out. 6 * * * Request timed out. 7 * * * Request timed out. 8 * * * Request timed out. 9 * * * Request timed out. 10 * * * Request timed out. 11 * * * Request timed out. 12 * * * Request timed out. 13 * * * Request timed out. 14 * * * Request timed out. 15 * * * Request timed out. 16 * * * Request timed out. 17 * * * Request timed out. 18 * * * Request timed out. 19 * * * Request timed out. 20 * * * Request timed out. 21 * * * Request timed out. 22 * * * Request timed out. 23 * * * Request timed out. 24 * * * Request timed out. 25 * * * Request timed out. 26 * * * Request timed out. 27 * * * Request timed out. 28 * * * Request timed out. 29 * * * Request timed out. 30 * * * Request timed out. Trace complete.
On PC1, Telnet to Branch-1, and from Branch-1 Telnet to the nearest interface of the Hub router (192.168.0.1):
C:\> telnet 192.168.1.1 Trying 192.168.1.1 ...Open User Access Verification Password: cisco Branch-1> enable Password: class Branch-1#
Branch-1# telnet 192.168.0.1 Trying 192.168.0.1 ...Open User Access Verification Password: cisco Hub> enable Password: class Hub#
Hub# show ip nat statistics
Total translations: 0 (0 static, 0 dynamic, 0 extended)
Outside Interfaces: GigabitEthernet0/0/0
Inside Interfaces: Serial0/1/1 , Serial0/2/0 , Serial0/2/1
Hits: 8 Misses: 8
Expired translations: 8
Dynamic mappings:
-- Inside Source
access-list 1 pool LAN refCount 0
pool LAN: netmask 255.255.255.224
start 209.165.201.128 end 209.165.201.159
type generic, total addresses 32 , allocated 0 (0%), misses 0Hub# show running-config | include interface|ip nat
interface GigabitEthernet0/0/0
ip nat outside
interface GigabitEthernet0/0/1
interface Serial0/1/0
interface Serial0/1/1
ip nat inside
interface Serial0/2/0
ip nat inside
interface Serial0/2/1
ip nat inside
interface Vlan1
ip nat pool LAN 209.165.201.128 209.165.201.159 netmask 255.255.255.224
ip nat inside source list 1 pool LAN overloadWhat we learned:
- The trace from PC1 stops after the Hub (192.168.0.1). The Hub receives the packets but cannot forward them to the internet.
- Serial0/1/1, Serial0/2/0 and Serial0/2/1 are NAT inside interfaces, but Serial0/1/0 (the link to Branch-1) is not. Traffic from the Branch-1 LAN 192.168.1.0/24 is not translated to the public pool LAN, so the Internet Server does not receive it with a routable source address.
Problem 2: PC3 cannot reach its default gateway
PC3 cannot ping the internet server. Further, it is found that it cannot ping its gateway or other devices on the network.
These tests indicate that the issue is either with the gateway or with the PC itself. Inspection of the IP addressing of PC3 shows that the addressing is correct. In addition, a green link light shows at the PC, so the link between the PC and LAN switch is up. Students should know from their documentation that PC2 is connected to the Factory router, as is PC3. Because PC3 can’t ping its gateway, the student should telnet from PC2 to the router to inspect its configuration.
From PC3, ping the default gateway and PC2 (192.168.3.50):
C:\> ping 192.168.4.1
Pinging 192.168.4.1 with 32 bytes of data:
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Ping statistics for 192.168.4.1:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),C:\> ping 192.168.3.50
Pinging 192.168.3.50 with 32 bytes of data:
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Ping statistics for 192.168.3.50:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),On PC2, Telnet to the Factory router through the default gateway:
C:\> telnet 192.168.3.1 Trying 192.168.3.1 ...Open User Access Verification Password: cisco Factory> enable Password: class Factory#
Factory# show ip interface brief
Interface IP-Address OK? Method Status Protocol
GigabitEthernet0/0/0 192.168.3.1 YES manual up up
GigabitEthernet0/0/1 192.168.4.1 YES manual administratively down down
Serial0/1/0 192.168.0.14 YES manual up up
Serial0/1/1 unassigned YES unset administratively down down
Vlan1 unassigned YES unset administratively down downWhat we learned:
The GigabitEthernet0/0/1 interface of the Factory router (192.168.4.1, the gateway of PC3) is administratively down.
Problem 3: The 192.168.4.0/24 network is not advertised
Even after the LAN interface for PC3 is activated, no devices can ping PC3 except for PC2, whose LAN 192.168.3.0/24 is also directly connected to the Factory router. Similarly, PC3 cannot ping any device beyond the Factory router. The Hub has no route to 192.168.4.0/24, so replies to PC3 cannot return.
Factory# show running-config | section router ospf router ospf 10 log-adjacency-changes network 192.168.3.0 0.0.0.255 area 0 network 192.168.0.12 0.0.0.3 area 0
What we learned:
The Hub routing table test in Fix 2 shows % Network not in table for 192.168.4.0. The Factory router runs OSPF process 10. It advertises 192.168.3.0/24 and the WAN link 192.168.0.12/30, but the network statement for the PC3 LAN, 192.168.4.0/24, is missing.
Problem 4: PC5 cannot reach other networks
PC5 can ping its default gateway. However, it cannot ping other PCs on the network or Internet Server.
While it is tempting to go directly to the gateway router to look for the problem, inspection of PC5 addressing shows that it is missing its default gateway address. The address should be available in the network documentation or by accessing the HQ router from another PC that has connectivity.
What we learned:
The ipconfig /all output of PC5 in Part 1 shows Default Gateway 0.0.0.0. PC5 can reach 192.168.5.129 because it is in the same subnet, but it cannot send traffic to any other network. The documentation shows that the gateway for VLAN 10 (192.168.5.128/25) is 192.168.5.129 on HQ G0/0/0.10.
Problem 5: Branch-2 has no route to the Internet Server
PC6 and PC7 can ping their default gateway addresses and each other but cannot ping the internet server. In fact, the default gateway router returns a destination host unreachable message, which usually means that a route to the destination network is not known by the gateway router.
The default gateway router, Branch-2, probably does not have a route to reach the internet server. The student should access the default gateway router and display the routing table. Students should see that no routes have been received through OSPF, including the default route. OSPF appears to be correctly configured, so the problem must be with the link over which the router should have received the OSPF updates.
From PC6, ping PC7 (192.168.2.67) in the other Branch-2 VLAN:
C:\> ping 192.168.2.67 Pinging 192.168.2.67 with 32 bytes of data: Request timed out. Reply from 192.168.2.67: bytes=32 time<1ms TTL=127 Reply from 192.168.2.67: bytes=32 time<1ms TTL=127 Reply from 192.168.2.67: bytes=32 time<1ms TTL=127 Ping statistics for 192.168.2.67: Packets: Sent = 4, Received = 3, Lost = 1 (25% loss), Approximate round trip times in milli-seconds: Minimum = 0ms, Maximum = 0ms, Average = 0ms
Note: The first request times out while ARP resolves the MAC addresses; this is normal. TTL=127 shows that the packets pass through one router (Branch-2), so inter-VLAN routing on Branch-2 works. The fault is not on the LAN side.
On PC6, Telnet to the Branch-2 router through the default gateway:
C:\> telnet 192.168.2.33 Trying 192.168.2.33 ...Open User Access Verification Password: cisco Branch-2> enable Password: class Branch-2#
Branch-2# show ip interface brief
Interface IP-Address OK? Method Status Protocol
GigabitEthernet0/0/0 unassigned YES manual up up
GigabitEthernet0/0/0.1 192.168.2.1 YES manual up up
GigabitEthernet0/0/0.32192.168.2.33 YES manual up up
GigabitEthernet0/0/0.64192.168.2.65 YES manual up up
GigabitEthernet0/0/1 unassigned YES unset administratively down down
Serial0/1/0 192.168.0.17 YES manual up up
Serial0/1/1 unassigned YES unset administratively down down
Vlan1 unassigned YES unset administratively down downBranch-2# show cdp neighbors detail Device ID: SW-B2 Entry address(es): IP address : 192.168.2.17 Platform: cisco 2960, Capabilities: Switch Interface: GigabitEthernet0/0/0.1, Port ID (outgoing port): GigabitEthernet0/1 Holdtime: 146 Version : Cisco IOS Software, C2960 Software (C2960-LANBASE-M), Version 12.2(25)FX, RELEASE SOFTWARE (fc1) Copyright (c) 1986-2005 by Cisco Systems, Inc. Compiled Wed 12-Oct-05 22:05 by pt_team advertisement version: 2 Duplex: full ------------------------- Device ID: Hub Entry address(es): IP address : 192.168.0.5 Platform: cisco ISR4300, Capabilities: Router Interface: Serial0/1/0, Port ID (outgoing port): Serial0/1/1 Holdtime: 146 Version : Cisco IOS XE Software, Version 03.13.04.S - Extended Support Release Cisco IOS Software, ISR Software (X86_64_LINUX_IOSD-UNIVERSALK9-M), Version 15.5(3)S5, RELEASE SOFTWARE (fc2) Technical Support: http://www.cisco.com/techsupport Copyright (c) 1986-2017 by Cisco Systems, Inc. Compiled Mon 05-Oct-15 11:24 by mcpre advertisement version: 2 Duplex: full
Branch-2# show ip route
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is not set
192.168.0.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.0.16/30 is directly connected, Serial0/1/0
L 192.168.0.17/32 is directly connected, Serial0/1/0
192.168.2.0/24 is variably subnetted, 6 subnets, 2 masks
C 192.168.2.0/27 is directly connected, GigabitEthernet0/0/0.1
L 192.168.2.1/32 is directly connected, GigabitEthernet0/0/0.1
C 192.168.2.32/27 is directly connected, GigabitEthernet0/0/0.32
L 192.168.2.33/32 is directly connected, GigabitEthernet0/0/0.32
C 192.168.2.64/27 is directly connected, GigabitEthernet0/0/0.64
L 192.168.2.65/32 is directly connected, GigabitEthernet0/0/0.64Branch-2# show ip ospf neighbor Branch-2#
Branch-2# show running-config | section router ospf
router ospf 10
log-adjacency-changes
network 192.168.0.4 0.0.0.3 area 0
network 192.168.2.0 0.0.0.127 area 0What we learned:
- The Serial0/1/0 interface of Branch-2 has the IP address 192.168.0.17. The documentation shows that it must be 192.168.0.6/30, in the same subnet as Hub S0/1/1 (192.168.0.5/30).
- The routing table has only connected routes and Gateway of last resort is not set. The OSPF neighbor table is empty.
- The OSPF configuration is correct: network 192.168.0.4 0.0.0.3 area 0 matches the documented link 192.168.0.4/30. Because S0/1/0 is in 192.168.0.16/30, this statement does not match the interface, so OSPF never runs on S0/1/0.
- CDP still shows the Hub on Serial0/1/0 because CDP works at Layer 2. However, the two ends are in different IP subnets, so no OSPF adjacency forms and Branch-2 learns no routes.
- The other Branch-2 settings match the documentation: subinterfaces .1, .32, and .64, and SW-B2 at 192.168.2.17.
Part 3: Repair the Network
After locating the issues, reconfigure the devices to repair the connectivity problem. Use your documentation from the previous activity to help you.
Fix 1: Hub - add ip nat inside on S0/1/0
Students should Telnet to the nearest interface of the Hub router and inspect its configuration. There, the student will discover that the ip nat inside configuration statement is missing from the interface that connects the Hub router to the Branch-1 router. This statement should be added to the configuration and PC1 should now be able to reach Internet Server.
Hub(config)# interface serial 0/1/0 Hub(config-if)# ip nat inside
Hub# show ip nat statistics
Total translations: 0 (0 static, 0 dynamic, 0 extended)
Outside Interfaces: GigabitEthernet0/0/0
Inside Interfaces: Serial0/1/0 , Serial0/1/1 , Serial0/2/0 , Serial0/2/1
Hits: 0 Misses: 0
Expired translations: 0
Dynamic mappings:
-- Inside Source
access-list 1 pool LAN refCount 0
pool LAN: netmask 255.255.255.224
start 209.165.201.128 end 209.165.201.159
type generic, total addresses 32 , allocated 0 (0%), misses 0C:\> ping 203.0.113.27
Pinging 203.0.113.27 with 32 bytes of data:
Reply from 203.0.113.27: bytes=32 time=13ms TTL=125
Reply from 203.0.113.27: bytes=32 time=8ms TTL=125
Reply from 203.0.113.27: bytes=32 time=6ms TTL=125
Reply from 203.0.113.27: bytes=32 time=7ms TTL=125
Ping statistics for 203.0.113.27:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 6ms, Maximum = 13ms, Average = 8msWhat we learned:
Serial0/1/0 is now listed as a NAT inside interface, and PC1 receives replies from the Internet Server.
Fix 2: Factory - activate G0/0/1
Activating the interface should enable PC3 to ping only its gateway and hosts on networks directly connected to the Factory router, such as PC2.
Note: Problem 2 hides Problem 3. While G0/0/1 is down, PC3 cannot even reach its gateway, so the missing OSPF network statement cannot be seen yet. After this fix, PC3 reaches its gateway but still not the Internet Server: the Hub does not know a route back to 192.168.4.0/24. Always re-test after each fix, because one fault can mask the next.
Factory(config)# interface gigabitethernet 0/0/1 Factory(config-if)# no shutdown
Factory# show ip interface brief
Interface IP-Address OK? Method Status Protocol
GigabitEthernet0/0/0 192.168.3.1 YES manual up up
GigabitEthernet0/0/1 192.168.4.1 YES manual up up
Serial0/1/0 192.168.0.14 YES manual up up
Serial0/1/1 unassigned YES unset administratively down down
Vlan1 unassigned YES unset administratively down downC:\> ping 192.168.4.1
Pinging 192.168.4.1 with 32 bytes of data:
Reply from 192.168.4.1: bytes=32 time<1ms TTL=255
Reply from 192.168.4.1: bytes=32 time<1ms TTL=255
Reply from 192.168.4.1: bytes=32 time=3ms TTL=255
Reply from 192.168.4.1: bytes=32 time<1ms TTL=255
Ping statistics for 192.168.4.1:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 3ms, Average = 0msHowever, PC3 still cannot reach the Internet Server, because the Hub has no route back to 192.168.4.0/24:
Hub# show ip route 192.168.4.0
% Network not in tableC:\> ping 203.0.113.27
Pinging 203.0.113.27 with 32 bytes of data:
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Ping statistics for 203.0.113.27:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),What we learned:
G0/0/1 is up/up and PC3 can now reach its default gateway 192.168.4.1. However, the Hub does not know the network 192.168.4.0/24, so replies from the Internet Server cannot return to PC3. This proves that Problem 3 is a separate fault.
Fix 3: Factory - advertise 192.168.4.0/24 in OSPF
Adding this network statement advertises 192.168.4.0/24 to the Hub through OSPF and restores connectivity to and from the LAN.
Factory(config)# router ospf 10 Factory(config-router)# network 192.168.4.0 0.0.0.255 area 0
Factory# show running-config | section router ospf
router ospf 10
log-adjacency-changes
network 192.168.3.0 0.0.0.255 area 0
network 192.168.0.12 0.0.0.3 area 0
network 192.168.4.0 0.0.0.255 area 0Hub# show ip route 192.168.4.0 Routing entry for 192.168.4.0/24 Known via "ospf 10", distance 110, metric 65, type intra area Last update from 192.168.0.14 on Serial0/2/1, 00:02:20 ago Routing Descriptor Blocks: * 192.168.0.14, from 192.168.3.1, on Serial0/2/1, 00:02:20 ago Route metric is 65, traffic share count is 1
C:\> ping 203.0.113.27
Pinging 203.0.113.27 with 32 bytes of data:
Reply from 203.0.113.27: bytes=32 time=17ms TTL=125
Reply from 203.0.113.27: bytes=32 time=9ms TTL=125
Reply from 203.0.113.27: bytes=32 time=1ms TTL=125
Reply from 203.0.113.27: bytes=32 time=1ms TTL=125
Ping statistics for 203.0.113.27:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 1ms, Maximum = 17ms, Average = 7msWhat we learned:
The PC3 LAN 192.168.4.0/24 is now advertised in OSPF process 10. The Hub learns it from Factory (192.168.0.14) on Serial0/2/1, so replies can return to PC3, and PC3 receives replies from the Internet Server.
Fix 4: PC5 - configure the default gateway
Adding the default gateway address solves the problem.
On PC5, click Desktop > IP Configuration and set the Default Gateway to 192.168.5.129.
C:\> ipconfig
FastEthernet0 Connection:(default port)
Connection-specific DNS Suffix..:
Link-local IPv6 Address.........: FE80::200:CFF:FE1B:50E7
IPv6 Address....................: ::
IPv4 Address....................: 192.168.5.227
Subnet Mask.....................: 255.255.255.128
Default Gateway.................: ::
192.168.5.129C:\> ping 203.0.113.27
Pinging 203.0.113.27 with 32 bytes of data:
Reply from 203.0.113.27: bytes=32 time=1ms TTL=125
Reply from 203.0.113.27: bytes=32 time=1ms TTL=125
Reply from 203.0.113.27: bytes=32 time=1ms TTL=125
Reply from 203.0.113.27: bytes=32 time=8ms TTL=125
Ping statistics for 203.0.113.27:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 1ms, Maximum = 8ms, Average = 2msWhat we learned:
PC5 now uses 192.168.5.129 as its default gateway and receives replies from the Internet Server.
Fix 5: Branch-2 - correct the S0/1/0 IP address
The address should be changed to 192.168.0.6/30. This will restore Layer 3 connectivity with the Hub router and allow OSPF updates to be received.
Branch-2(config)# interface serial 0/1/0 Branch-2(config-if)# ip address 192.168.0.6 255.255.255.252
Branch-2# show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
192.168.0.13 0 FULL/ - 00:00:32 192.168.0.5 Serial0/1/0Branch-2# show ip route ospf
192.168.0.0/24 is variably subnetted, 5 subnets, 2 masks
O 192.168.0.0 [110/128] via 192.168.0.5, 00:10:49, Serial0/1/0
O 192.168.0.8 [110/128] via 192.168.0.5, 00:10:49, Serial0/1/0
O 192.168.0.12 [110/128] via 192.168.0.5, 00:10:49, Serial0/1/0
O 192.168.1.0 [110/129] via 192.168.0.5, 00:10:49, Serial0/1/0
O 192.168.3.0 [110/129] via 192.168.0.5, 00:10:49, Serial0/1/0
O 192.168.4.0 [110/129] via 192.168.0.5, 00:10:49, Serial0/1/0
192.168.5.0/25 is subnetted, 2 subnets
O 192.168.5.0 [110/129] via 192.168.0.5, 00:10:49, Serial0/1/0
O 192.168.5.128 [110/129] via 192.168.0.5, 00:10:49, Serial0/1/0
O 192.168.6.0 [110/129] via 192.168.0.5, 00:10:49, Serial0/1/0
O*E2 0.0.0.0/0 [110/1] via 192.168.0.5, 00:10:49, Serial0/1/0C:\> ping 203.0.113.27
Pinging 203.0.113.27 with 32 bytes of data:
Reply from 203.0.113.27: bytes=32 time=14ms TTL=125
Reply from 203.0.113.27: bytes=32 time=4ms TTL=125
Reply from 203.0.113.27: bytes=32 time=21ms TTL=125
Reply from 203.0.113.27: bytes=32 time=8ms TTL=125
Ping statistics for 203.0.113.27:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 4ms, Maximum = 21ms, Average = 11msWhat we learned:
Branch-2 forms a FULL adjacency with the Hub (neighbor ID 192.168.0.13) over Serial0/1/0 and learns all OSPF routes, including the default route O*E2 0.0.0.0/0. PC6 receives replies from the Internet Server.
Part 4: Document the Issues
Record your issues in the table below.
| Device | Issue | Action |
|---|---|---|
| Hub | The ip nat inside command is missing on S0/1/0 (link to Branch-1). Traffic from PC1 is not translated, so PC1 cannot reach the Internet Server. | interface serial 0/1/0ip nat inside |
| Factory | G0/0/1 (192.168.4.1, gateway of PC3) is administratively down. PC3 cannot reach its gateway. | interface gigabitethernet 0/0/1no shutdown |
| Factory | The OSPF process 10 has no network statement for 192.168.4.0/24, so the PC3 LAN is not advertised and the Hub has no route back to it. | router ospf 10network 192.168.4.0 0.0.0.255 area 0 |
| PC5 | The default gateway is 0.0.0.0. PC5 can reach only its own subnet. | Set the default gateway to 192.168.5.129 (Desktop > IP Configuration). |
| Branch-2 | S0/1/0 has the wrong IP address 192.168.0.17. No OSPF adjacency forms with the Hub, so Branch-2 has no route to the Internet Server. | interface serial 0/1/0ip address 192.168.0.6 255.255.255.252 |
Note: Problems 2 and 3 are both on the Factory router but are two distinct faults (a shut interface and a missing OSPF network statement), so they occupy two separate rows even though both affect PC3.
Final Verification
After all five fixes, every PC should be able to ping every other PC and the Internet Server.
C:\> ping 203.0.113.27
Pinging 203.0.113.27 with 32 bytes of data:
Reply from 203.0.113.27: bytes=32 time=1ms TTL=125
Reply from 203.0.113.27: bytes=32 time=8ms TTL=125
Reply from 203.0.113.27: bytes=32 time=10ms TTL=125
Reply from 203.0.113.27: bytes=32 time=5ms TTL=125
Ping statistics for 203.0.113.27:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 1ms, Maximum = 10ms, Average = 6msDevice Configs - Final
ROUTER Hub
! ============================================================== !--- 12.6.2 Packet Tracer - Troubleshooting Challenge - Use Documentation to Solve Issues !--- ANSWER SCRIPT FOR ROUTER Hub !--- Usage: from PC1, telnet 192.168.1.1 (Branch-1), then telnet 192.168.0.1, then paste this whole file at the Hub> prompt (VTY password cisco, enable secret class). Every line beginning with "!" is a comment; IOS ignores it. ! ============================================================== enable configure terminal ! -------------------------------------------------------------- !--- Problem 1 ! -------------------------------------------------------------- !--- S0/1/0 (link to Branch-1) must be a NAT inside interface. interface serial 0/1/0 ip nat inside exit end ! -------------------------------------------------------------- !--- Save the configuration to NVRAM. (Press Enter when prompted for the destination filename.) ! -------------------------------------------------------------- copy running-config startup-config ! ============================================================== !--- Verification: !--- show ip nat statistics -> Inside Interfaces include Serial0/1/0 !--- PC1: ping 203.0.113.27 -> replies ! ==============================================================
ROUTER Factory
! ============================================================== !--- 12.6.2 Packet Tracer - Troubleshooting Challenge - Use Documentation to Solve Issues !--- ANSWER SCRIPT FOR ROUTER Factory !--- Usage: from PC2, telnet 192.168.3.1, then paste this whole file at the Factory> prompt (VTY password cisco, enable secret class). Every line beginning with "!" is a comment; IOS ignores it. ! ============================================================== enable configure terminal ! -------------------------------------------------------------- !--- Problem 2 ! -------------------------------------------------------------- !--- Activate G0/0/1, the gateway interface of PC3. interface gigabitethernet 0/0/1 no shutdown exit ! -------------------------------------------------------------- !--- Problem 3 ! -------------------------------------------------------------- !--- Advertise the PC3 LAN in the existing OSPF process 10. router ospf 10 network 192.168.4.0 0.0.0.255 area 0 exit end ! -------------------------------------------------------------- !--- Save the configuration to NVRAM. (Press Enter when prompted for the destination filename.) ! -------------------------------------------------------------- copy running-config startup-config ! ============================================================== !--- Verification: !--- show ip interface brief -> G0/0/1 up/up !--- PC3: ping 192.168.4.1 and 203.0.113.27 -> replies ! ==============================================================
ROUTER Branch-2
! ============================================================== !--- 12.6.2 Packet Tracer - Troubleshooting Challenge - Use Documentation to Solve Issues !--- ANSWER SCRIPT FOR ROUTER Branch-2 !--- Usage: from PC6, telnet 192.168.2.33, then paste this whole file at the Branch-2> prompt (VTY password cisco, enable secret class). Every line beginning with "!" is a comment; IOS ignores it. ! ============================================================== enable configure terminal ! -------------------------------------------------------------- !--- Problem 5 ! -------------------------------------------------------------- !--- Correct the IP address of S0/1/0 (link to Hub S0/1/1, 192.168.0.5/30). interface serial 0/1/0 ip address 192.168.0.6 255.255.255.252 exit end ! -------------------------------------------------------------- !--- Save the configuration to NVRAM. (Press Enter when prompted for the destination filename.) ! -------------------------------------------------------------- copy running-config startup-config ! ============================================================== !--- Verification: !--- show ip ospf neighbor -> Hub (192.168.0.13) in FULL state !--- show ip route ospf -> O*E2 0.0.0.0/0 default route !--- PC6, PC7: ping 203.0.113.27 -> replies ! ==============================================================
PC5
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