Download Troubleshooting and Maintaining Cisco IP Networks (TSHOOT v2-0).PracticeTest.300-135.2018-08-22.1e.70q.vcex

Instructions  
This item contains a trouble ticket covering a single network topology. You will need to troubleshoot the problem by issuing commands on the devices. To begin troubleshooting a ticket, click on the BLUE trouble ticket button on the right. 
For each ticket, you will be required to answer the following three questions:
Which of the following devices is the source of the problem? 
Which of the following technologies is the source of the problem? 
Which of the following is most likely to solve the problem? 
Although the ticket scenarios might look similar, the devices are configured differently for each ticket. You can access a device by clicking on its button at the bottom of the screen or by clicking on its picture in any of the topology diagrams. You can open the topology diagrams by clicking on the topology buttons at the bottom of the screen. You can have multiple devices and topology diagrams open at the same time. 
You can access the following devices for each trouble ticket:
R1, R2, R3, and R4: Cisco 2600s
R5: Cisco 3640
DS1 and DS2: Cisco Catalyst 3560s
AS1: Cisco Catalyst 2912XL
PC1: Windows-based client operating system
Not all commands are available on each device. Only certain show, ping, and traceroute commands are available on the routers and switches. Only the ping and ipconfig commands are available on PC1. You cannot access the ISP router or any of the servers. 
You can move among the three questions in the trouble ticket by clicking Previous Question and Next Question. After you have answered the third question, you can click Done to complete the trouble ticket. In study mode, you can complete a trouble ticket and display the explanation by clicking Done + Show Explanation. However, once you have clicked either of these two GREEN buttons, your responses will be recorded and the ticket button will turn RED. In simulation mode, you will be unable to reopen the ticket. 
Click the CLOSE button at the bottom right when you are ready to end the troubleshooting simulation. 
Layer 2 Topology 

• A: NTP
• B: OSPFv2
• C: OSPFv3
• D: EIGRP
• E: redistribution
• F: Layer 3 addressing
• G: interface

Correct Answer: B

Instructions  
This item contains a trouble ticket covering a single network topology. You will need to troubleshoot the problem by issuing commands on the devices. To begin troubleshooting a ticket, click on the BLUE trouble ticket button on the right. 
For each ticket, you will be required to answer the following three questions:
Which of the following devices is the source of the problem? 
Which of the following technologies is the source of the problem? 
Which of the following is most likely to solve the problem? 
Although the ticket scenarios might look similar, the devices are configured differently for each ticket. You can access a device by clicking on its button at the bottom of the screen or by clicking on its picture in any of the topology diagrams. You can open the topology diagrams by clicking on the topology buttons at the bottom of the screen. You can have multiple devices and topology diagrams open at the same time. 
You can access the following devices for each trouble ticket:
R1, R2, R3, and R4: Cisco 2600s
R5: Cisco 3640
DS1 and DS2: Cisco Catalyst 3560s
AS1: Cisco Catalyst 2912XL
PC1: Windows-based client operating system
Not all commands are available on each device. Only certain show, ping, and traceroute commands are available on the routers and switches. Only the ping and ipconfig commands are available on PC1. You cannot access the ISP router or any of the servers. 
You can move among the three questions in the trouble ticket by clicking Previous Question and Next Question. After you have answered the third question, you can click Done to complete the trouble ticket. In study mode, you can complete a trouble ticket and display the explanation by clicking Done + Show Explanation. However, once you have clicked either of these two GREEN buttons, your responses will be recorded and the ticket button will turn RED. In simulation mode, you will be unable to reopen the ticket. 
Click the CLOSE button at the bottom right when you are ready to end the troubleshooting simulation. 
Layer 2 Topology 

• A: issuing the network 192.168.1.4 0.0.0.3 area 0 command
• B: issuing the network 192.168.1.8 0.0.0.3 area 0 command
• C: issuing the area 2 virtual-link 192.168.99.5 command
• D: enabling OSPF MD5 authentication on the S1.0.324 interface
• E: changing the OSPF network type on the S1.0.324 interface
• F: changing the OSPF area type
• G: changing the masks on the OSPF network statement
• H: issuing the no ip ospf hello-interval command on the S1.0.324 interface
• I: changing the OSPF router ID

Correct Answer: D

You should enable Open Shortest Path First version 2 (OSPFv2) Message Digest 5 (MD5) authentication on the S1/0.324 interface of R3. To determine which device is the source of the problem, you can issue the ping and traceroute commands to test connectivity between devices. You can use any troubleshooting method you want, as long as you follow a systematic procedure. For example, you can ping from PC1 to the farthest device and work your way back to PC1 until pings are successful.  
Pings from PC1 to the S1/0.423 interface of R4 are successful. However, pings from PC1 to the S1/1.324 interface of R3 time out and fail. Pings from R1 to R3 are successful, but pings from R1 to R4 are not. Therefore, the problem likely exists on R3 or R4.  
Once you have determined where connectivity is lost, you can begin to troubleshoot what is causing the problem. Issuing the show running-config command on R4 indicates that OSPF MD5 authentication is enabled on the S1/0.423 interface of R4, as shown in the following partial output: 

   

However, OSPF MD5 authentication is not enabled on the S1/0.324 interface of R3. An OSPF adjacency will not be established unless neither side or both sides of the link are configured with authentication; if authentication is configured, then the authentication key must match. 
OSPF authentication can be enabled for an interface or for an area. To configure OSPF MD5 authentication for an interface, you should issue the ip osp authentication message-digest command in interface configuration mode. To configure OSPF MD5 authentication for an entire area, you would issue the area area-id authentication message-digest command in router configuration mode. To configure the key that should be used for MD5 authentication, you should issue the ip ospf message-digest-key key-id md5 key command in interface configuration mode.  
You should not change the OSPF area type on any of the routers, because the area types already match between the devices. The following parameters must match for devices to establish on OSPF adjacency: 
Hello timer 
Dead timer 
Area number and type 
Network type 
Subnet 
Authentication type and password 
In addition, OSPF cannot establish an adjacency over a secondary IP address. 
You need not change the router ID on R3. As long as the router ID is unique, OSPF routers will from an adjacency. The first line in the output of the show ip ospf command displays the router ID. To change the router ID on a router, you would issue the router-id A.B.C.D command from OSPF router configuration mode, where A.B.C.D is a 32-bit router ID in dotted decimal notation. 
You need not change the OSPF network type on any of the devices on the network. The OSPF network type must match so that connected interfaces can form an adjacency. The S1/0.324 interface on R3 and the S1/0.423 interface on R4 are both set to the point-to-point OSPF network type. You can determine the OSPF network type by issuing the show ip ospf interface command, as shown in the following partial output:

   

To change the OSPF network type for an interface, you would issue the ip ospf network {broadcast | non-broadcast | point-to-multipoint | point-to-point} command from interface configuration mode. 
You need not issue the no ip ospf hello-interval command on any of the devices on the network, because they are all using the default hello timer settings. By default, the hello timer is set to 10 seconds on point-to-point and broadcast links and 30 seconds on nonbroadcast multiaccess (NBMA) links. You can verify the hello timer settings by issuing the show ip ospf interface command.   
You need not to issue the network 192.168.1.4  0.0.0.3 area 0 command or the network 192.168.1.8  0.0.0.3 area 0 command on R3, because these commands have already been issued. Additionally, you should not change the masks on the network statements, because the network command uses wildcard masks, not subnet masks. A wildcard mask is basically an inverse subnet mask. To calculate the appropriate wildcard mask, you should subtract the subnet mask from 255.255.255.255. For example, the 192.168.1.8 network has a /30 subnet mask, which is 255.255.255.252. Subtracting 255.255.255.252 from 255.255.255.255 yields a wildcard mask of 0.0.0.3.  
You need not change the OSPF routing process on R5 to 15, nor do you need to change the OSPF routing process on the other devices to 10. The OSPF routing process number is locally significant, so two OSPF routers with different routing process numbers can still form an adjacency.  
All areas in an OSPF internetwork must be connected to the backbone area, Area 0. A virtual link must be created between two area border routers (ABRs) to connect a remote area to the backbone area through a transit area. Only the ABRs that connect to the transit area must be configured with a virtual link; therefore, you should not issue the area 1 virtual-link 192.168.1.13 command or the area 2 virtual-link 192.168.99.4 command on DS2.  
R4 and R5 are already configured with the proper area virtual-link commands. The syntax of the area virtual-link command is area area-id virtual-link router-id, where area-id is the transit area ID and router-id of the router at the other end of the virtual link. You should not issue the area 2 virtual-link 192.168.99.5 command on R4 or the area 2 virtual-link 192.168.99.4 command on R5, because Area 1, not Area 2, is the transit area. You should not issue the area 1 virtual-link 192.168.1.14 command on R4 or the area 1 virtual-link 192.168.1.13 command on R5, because you should use the router ID of the router at the other end of the virtual link for the router-id parameter; you should not use the router’s interface IP address. You should not issue the area 2 virtual-link 192.168.99.5 command on R3, because R3 is not connected to the transit area.  
Reference: 
https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13697-25.html
https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13699-29.html#seventh
https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/47866-ospfdb7.html

Instructions  
This item contains a trouble ticket covering a single network topology. You will need to troubleshoot the problem by issuing commands on the devices. To begin troubleshooting a ticket, click on the BLUE trouble ticket button on the right. 
For each ticket, you will be required to answer the following three questions:
Which of the following devices is the source of the problem? 
Which of the following technologies is the source of the problem? 
Which of the following is most likely to solve the problem? 
Although the ticket scenarios might look similar, the devices are configured differently for each ticket. You can access a device by clicking on its button at the bottom of the screen or by clicking on its picture in any of the topology diagrams. You can open the topology diagrams by clicking on the topology buttons at the bottom of the screen. You can have multiple devices and topology diagrams open at the same time. 
You can access the following devices for each trouble ticket:
R1, R2, R3, and R4: Cisco 2600s
R5: Cisco 3640
DS1 and DS2: Cisco Catalyst 3560s
AS1: Cisco Catalyst 2912XL
PC1: Windows-based client operating system
Not all commands are available on each device. Only certain show, ping, and traceroute commands are available on the routers and switches. Only the ping and ipconfig commands are available on PC1. You cannot access the ISP router or any of the servers. 
You can move among the three questions in the trouble ticket by clicking Previous Question and Next Question. After you have answered the third question, you can click Done to complete the trouble ticket. In study mode, you can complete a trouble ticket and display the explanation by clicking Done + Show Explanation. However, once you have clicked either of these two GREEN buttons, your responses will be recorded and the ticket button will turn RED. In simulation mode, you will be unable to reopen the ticket. 
Click the CLOSE button at the bottom right when you are ready to end the troubleshooting simulation. 
Layer 2 Topology 

• A: R1
• B: R2
• C: R3
• D: R4
• E: R5
• F: DS1
• G: DS2
• H: AS1

Correct Answer: D

Instructions  
This item contains a trouble ticket covering a single network topology. You will need to troubleshoot the problem by issuing commands on the devices. To begin troubleshooting a ticket, click on the BLUE trouble ticket button on the right. 
For each ticket, you will be required to answer the following three questions:
Which of the following devices is the source of the problem? 
Which of the following technologies is the source of the problem? 
Which of the following is most likely to solve the problem? 
Although the ticket scenarios might look similar, the devices are configured differently for each ticket. You can access a device by clicking on its button at the bottom of the screen or by clicking on its picture in any of the topology diagrams. You can open the topology diagrams by clicking on the topology buttons at the bottom of the screen. You can have multiple devices and topology diagrams open at the same time. 
You can access the following devices for each trouble ticket:
R1, R2, R3, and R4: Cisco 2600s
R5: Cisco 3640
DS1 and DS2: Cisco Catalyst 3560s
AS1: Cisco Catalyst 2912XL
PC1: Windows-based client operating system
Not all commands are available on each device. Only certain show, ping, and traceroute commands are available on the routers and switches. Only the ping and ipconfig commands are available on PC1. You cannot access the ISP router or any of the servers. 
You can move among the three questions in the trouble ticket by clicking Previous Question and Next Question. After you have answered the third question, you can click Done to complete the trouble ticket. In study mode, you can complete a trouble ticket and display the explanation by clicking Done + Show Explanation. However, once you have clicked either of these two GREEN buttons, your responses will be recorded and the ticket button will turn RED. In simulation mode, you will be unable to reopen the ticket. 
Click the CLOSE button at the bottom right when you are ready to end the troubleshooting simulation. 
Layer 2 Topology 

• A: NTP
• B: GRE
• C: OSPFv2
• D: OSPFv3
• E: redistribution
• F: DHCP
• G: Layer 3 addressing
• H: interface

Correct Answer: F

Instructions  
This item contains a trouble ticket covering a single network topology. You will need to troubleshoot the problem by issuing commands on the devices. To begin troubleshooting a ticket, click on the BLUE trouble ticket button on the right. 
For each ticket, you will be required to answer the following three questions:
Which of the following devices is the source of the problem? 
Which of the following technologies is the source of the problem? 
Which of the following is most likely to solve the problem? 
Although the ticket scenarios might look similar, the devices are configured differently for each ticket. You can access a device by clicking on its button at the bottom of the screen or by clicking on its picture in any of the topology diagrams. You can open the topology diagrams by clicking on the topology buttons at the bottom of the screen. You can have multiple devices and topology diagrams open at the same time. 
You can access the following devices for each trouble ticket:
R1, R2, R3, and R4: Cisco 2600s
R5: Cisco 3640
DS1 and DS2: Cisco Catalyst 3560s
AS1: Cisco Catalyst 2912XL
PC1: Windows-based client operating system
Not all commands are available on each device. Only certain show, ping, and traceroute commands are available on the routers and switches. Only the ping and ipconfig commands are available on PC1. You cannot access the ISP router or any of the servers. 
You can move among the three questions in the trouble ticket by clicking Previous Question and Next Question. After you have answered the third question, you can click Done to complete the trouble ticket. In study mode, you can complete a trouble ticket and display the explanation by clicking Done + Show Explanation. However, once you have clicked either of these two GREEN buttons, your responses will be recorded and the ticket button will turn RED. In simulation mode, you will be unable to reopen the ticket. 
Click the CLOSE button at the bottom right when you are ready to end the troubleshooting simulation. 
Layer 2 Topology 

• A: creating a new DHCP pool
• B: modifying the DHCP exclusion range
• C: modifying the IP address range assigned by the DHCP pool
• D: changing the default router assigned by the DHCP pool
• E: adding a default DNS server to the DHCP pool
• F: creating an IP helper address
• G: issuing the ip forward-protocol udp 68 command.

Correct Answer: B

You should modify the Dynamic Host Configuration Protocol (DHCP) exclusion range on R4. To determine which device is the source of the problem, you can issue the ping and traceroute commands to test connectivity between devices. You can use any troubleshooting method you want, as long as you follow a systematic procedure. For example, you can ping from PC1 to the closest device and work your way up the network until communication is lost, or you can ping from PC1 to the farthest device and work your way back to PC1 until pings are successful.  
In this scenario, PC1 is unable to ping any device on the network except 10.10.22.11. Issuing the ipconfig command on PC1 will display the following output: 

   

Issuing the show running-config command on DS1 will reveal that 10.10.22.11 is assigned to the virtual LAN (VLAN) 22 interface of DS1:

   

Therefore, the DHCP server, R4, has assigned PC1 the same IP address as the one configured on the Fa0/1 interface of DS1. Issuing the show ip dhcp binding command on R4 confirms that R4 assigned the IP address to PC1, as shown in the following output:

   

R4 should be configured with an exclusion range so that DHCP clients are not assigned IP addresses to servers and static network devices. The ip dhcp excluded-address start-address end-address command is used to exclude from DHCP the range of addresses from start-address through end-address. Issuing the show running-config command on R4 displays the following partial output:
ip dhcp excluded-address 10.10.22.1 10.10.22.10 
Issuing the ip dhcp excluded-address 10.10.22.1 10.10.22.30 command on R4 is sufficient to exclude the statically assigned devices on the network.  
You need not create a new DHCP pool on any of the devices on the network. Creating a new DHCP pool on another device with the same address range can cause IP address conflicts to arise if both DHCP servers assign the same IP address to two different devices. The ip dhcp pool pool-name command creates a DHCP pool and enters DHCP configuration mode, in which you can configure various DHCP client options.  
You should not modify the IP address range assigned by the DHCP pool. The DHCP pool must assign addresses from the 10.10.22.0/24 network so that DHCP clients in VLAN 22 can receive IP addresses. The network address subnet command specifies the range of IP addresses that will be issued by DHCP.  
You should not change the default router assigned by the DHCP pool. Clients in VLAN 22 should use the default gateway at 10.10.22.25, which is the shared gateway used by the Hot Standby Router Protocol (HSRP) switches, DS1 and DS2. The default-router address command specifies the default gateway that is assigned to clients by the DHCP server. 
You need not add a Domain Name System (DNS) server to the DHCP pool. DNS servers are used for domain name-to-IP address resolution. PC1 cannot ping the server 210.98.76.54 by its IP address, so a DNS server is unnecessary. The dns-server address command specifies the DNS server address that is assigned to clients by the DHCP server.  
You need not create an IP helper address. DS1 and DS2 are already configured with an IP helper address so that DHCP requests from VLAN 22 can reach R4. The ip helper-address command is used to forward User Datagram Protocol (UDP) broadcasts to a remote server or device. DHCP requests use UDP broadcasts, so a device configured as an IP helper can intercept a DHCP request and forward it to a DHCP server on a remote subnet. The address lease process and other communications are then returned to the originating subnet.  
You need not issue the ip forward-protocol udp 68 command. The ip forward-protocol command is used to specify the UDP port numbers that should be forwarded by the ip helper-address commands. By default, the ip helper-address command forwards broadcasts to the following UDP ports: 

   

Because DHCP client requests are already being sent by the ip helper-address command, the ip forward-protocol udp 68 command is unnecessary.  
Reference: https://www.cisco.com/c/en/us/td/docs/ios/12_2/ip/configuration/guide/fipr_c/1cfdhcp.html

Instructions  
This item contains a trouble ticket covering a single network topology. You will need to troubleshoot the problem by issuing commands on the devices. To begin troubleshooting a ticket, click on the BLUE trouble ticket button on the right. 
For each ticket, you will be required to answer the following three questions:
Which of the following devices is the source of the problem? 
Which of the following technologies is the source of the problem? 
Which of the following is most likely to solve the problem? 
Although the ticket scenarios might look similar, the devices are configured differently for each ticket. You can access a device by clicking on its button at the bottom of the screen or by clicking on its picture in any of the topology diagrams. You can open the topology diagrams by clicking on the topology buttons at the bottom of the screen. You can have multiple devices and topology diagrams open at the same time. 
You can access the following devices for each trouble ticket:
R1, R2, R3, and R4: Cisco 2600s
R5: Cisco 3640
DS1 and DS2: Cisco Catalyst 3560s
AS1: Cisco Catalyst 2912XL
PC1: Windows-based client operating system
Not all commands are available on each device. Only certain show, ping, and traceroute commands are available on the routers and switches. Only the ping and ipconfig commands are available on PC1. You cannot access the ISP router or any of the servers. 
You can move among the three questions in the trouble ticket by clicking Previous Question and Next Question. After you have answered the third question, you can click Done to complete the trouble ticket. In study mode, you can complete a trouble ticket and display the explanation by clicking Done + Show Explanation. However, once you have clicked either of these two GREEN buttons, your responses will be recorded and the ticket button will turn RED. In simulation mode, you will be unable to reopen the ticket. 
Click the CLOSE button at the bottom right when you are ready to end the troubleshooting simulation. 
Layer 2 Topology 

• A: R1
• B: R2
• C: R3
• D: R4
• E: R5
• F: DS1
• G: DS2
• H: AS1

Correct Answer: C

Instructions  
This item contains a trouble ticket covering a single network topology. You will need to troubleshoot the problem by issuing commands on the devices. To begin troubleshooting a ticket, click on the BLUE trouble ticket button on the right. 
For each ticket, you will be required to answer the following three questions:
Which of the following devices is the source of the problem? 
Which of the following technologies is the source of the problem? 
Which of the following is most likely to solve the problem? 
Although the ticket scenarios might look similar, the devices are configured differently for each ticket. You can access a device by clicking on its button at the bottom of the screen or by clicking on its picture in any of the topology diagrams. You can open the topology diagrams by clicking on the topology buttons at the bottom of the screen. You can have multiple devices and topology diagrams open at the same time. 
You can access the following devices for each trouble ticket:
R1, R2, R3, and R4: Cisco 2600s
R5: Cisco 3640
DS1 and DS2: Cisco Catalyst 3560s
AS1: Cisco Catalyst 2912XL
PC1: Windows-based client operating system
Not all commands are available on each device. Only certain show, ping, and traceroute commands are available on the routers and switches. Only the ping and ipconfig commands are available on PC1. You cannot access the ISP router or any of the servers. 
You can move among the three questions in the trouble ticket by clicking Previous Question and Next Question. After you have answered the third question, you can click Done to complete the trouble ticket. In study mode, you can complete a trouble ticket and display the explanation by clicking Done + Show Explanation. However, once you have clicked either of these two GREEN buttons, your responses will be recorded and the ticket button will turn RED. In simulation mode, you will be unable to reopen the ticket. 
Click the CLOSE button at the bottom right when you are ready to end the troubleshooting simulation. 
Layer 2 Topology 

• A: NTP
• B: DHCP
• C: Layer 3 addressing
• D: Layer 3 security
• E: Layer 2 security
• F: STP
• G: Etherchannel
• H: VLAN configuration
• I: interface

Correct Answer: I

Instructions  
This item contains a trouble ticket covering a single network topology. You will need to troubleshoot the problem by issuing commands on the devices. To begin troubleshooting a ticket, click on the BLUE trouble ticket button on the right. 
For each ticket, you will be required to answer the following three questions:
Which of the following devices is the source of the problem? 
Which of the following technologies is the source of the problem? 
Which of the following is most likely to solve the problem? 
Although the ticket scenarios might look similar, the devices are configured differently for each ticket. You can access a device by clicking on its button at the bottom of the screen or by clicking on its picture in any of the topology diagrams. You can open the topology diagrams by clicking on the topology buttons at the bottom of the screen. You can have multiple devices and topology diagrams open at the same time. 
You can access the following devices for each trouble ticket:
R1, R2, R3, and R4: Cisco 2600s
R5: Cisco 3640
DS1 and DS2: Cisco Catalyst 3560s
AS1: Cisco Catalyst 2912XL
PC1: Windows-based client operating system
Not all commands are available on each device. Only certain show, ping, and traceroute commands are available on the routers and switches. Only the ping and ipconfig commands are available on PC1. You cannot access the ISP router or any of the servers. 
You can move among the three questions in the trouble ticket by clicking Previous Question and Next Question. After you have answered the third question, you can click Done to complete the trouble ticket. In study mode, you can complete a trouble ticket and display the explanation by clicking Done + Show Explanation. However, once you have clicked either of these two GREEN buttons, your responses will be recorded and the ticket button will turn RED. In simulation mode, you will be unable to reopen the ticket. 
Click the CLOSE button at the bottom right when you are ready to end the troubleshooting simulation. 
Layer 2 Topology 

• A: reconnecting the cable to the S1/0 interface
• B: issuing the no shutdown command on the S1/0 interface
• C: issuing the no shutdown command on the S1/0.322 and S1/0.324 subinterfaces
• D: issuing the clock rate 115200 command on the S1/0 interface
• E: issuing the encapsulation frame-relay command on the S1/0.322 and S1/0.324 subinterfaces
• F: creating Frame Relay maps on the S1/0.322 and S1/0.324 subinterfaces.

Correct Answer: D

You should issue the clock rate 115200 command on the S1/0 interface of R3. To determine which device is the source of the problem, you can issue the ping and traceroute commands to test connectivity between devices. You can use any troubleshooting method you want, as long as you follow a systematic procedure. For example, you can ping from PC1 to the closest device and work your way up the network until communication is lost, or you can ping from PC1 to the farthest device and work your way back to PC1 until pings are successful.  
In this scenario, if you were to ping the E0/0 interface of R4 from PC1, the pings would be successful, as shown in the following output:

   

However, if you were to ping the S1/0 interface of R4 from PC1, you would receive the following output: 

   

Therefore, the problem likely exists on R4 or beyond.  
Once you have determined where connectively is lost, you can begin to troubleshoot what is causing the problem. Issuing the show interfaces Serial 1/0 command on R4 reveals that the interface is up and the line protocol is up. However, issuing the show interfaces Serial 1/0.423 command on R4 reveals that the subinterface is down and the line protocol is down, as shown in the following partial output:

   

The interface status message Serial1/0 is down, line protocol is down often indicates that there is a problem at Layer 1 of the Open Systems Interconnection (OSI) model, which is the Physical layer. When you receive this interface status message, you should check both ends of the physical cable to see if they are securely connected to the proper interfaces. You can check whether the cable is disconnected from the S1/0 interface by issuing the show controllers Serial 1/0 command. If no cable is connected to the interface, you will receive the following partial output: 

   

However, in this scenario, the data terminal equipment (DTE) end of the serial cable is connected to R4, as shown by the following partial output from the show controllers Serial 1/0 command.  

   
 
Issuing the show interfaces Serial 1/0 command on R3 reveals that the interface is up and the line protocol is down, as shown in the following partial output:

   

The interface status message Serial1/0 is up, line protocol is down indicates that there is a problem at Layer 2 of the OSI model, which is the Data Link layer. If you receive this interface status message, you should check the encapsulation methods on the connected routers to ensure that they match. If the encapsulation methods match, you should check to ensure that the router connected to the data circuit-terminating equipment (DCE) end of the cable is providing clocking. To determine which end of the cable is connected to the router, you should issue the show controllers Serial 1/0 command. If you were to issue the show controllers Serial 1/0 command on R3, you would receive the following partial output: 

   
 
The DCE end of the serial cable typically provides clocking, and the DTE end of the serial cable does not. Issuing the show running-config command on R3 reveals that the clock rate command is missing on the S1/0 interface. To enable clocking on the interface, you should issue the clock rate bps command in interface configuration mode, where bps is the clock rate in bits per second. After you issue the clock rate 115200 command on R3, the output from the show interfaces Serial1/0 command on R3 and R4 will display the interface status message Serial1/0 is up, line protocol is up.  
You should not enable clocking on the S1/0 interface of R4. The output of the show controllers Serial 1/0 command on R4 indicates that the DTE end of the cable is connected to R4. Therefore, R4 does not need to provide clocking.  
You do not need to issue the no shutdown command on the S1/0 interface of R3. The no shutdown command is used to enable an interface that has been administratively shut down by the shutdown command. If the interface had been administratively shut down, you would have seen the following partial output from the show interfaces Serial 1/0 command: 

   

You cannot issue the encapsulation frame-relay command on the subinterfaces of R3. The encapsulation frame-relay command can be issued only on the S1/0 interface.  
You should not create Frame Relay maps on the subinterfaces. Frame Relay maps cannot be created on point-to-point subinterfaces. To create a Frame Relay map, you would issue the frame-relay map ip ip-address dlci [broadcast] [ ietf | cisco] command.  
You need not change the data link connection identifier (DLCI) on the subinterfaces. A DLCI is an address that uniquely identifies a permanent virtual circuit (PVC) connection in a Frame Relay circuit. Each DLCI is locally significant, which means that the routers at each end of the PVC can use different DLCIs to identify the same circuit.  
You need no change the interface type to point-to-multipoint on the subinterfaces. The S1/0 interface on R3 is currently configured so that it can communicate only with its upstream and downstream routers, not with all the routers attached to the Frame Relay cloud. If you were to change the interface type to point-to-multipoint, you would also have to configure Frame Relay maps. To configure the interface type for a subinterface, you would issue the interface type slot/ port.subinterface [multipoint | point-to-point] command.  
Reference:
https://www.cisco.com/en/US/docs/internetworking/troubleshooting/guide/tr1915.html#wp1020558

Instructions  
This item contains a trouble ticket covering a single network topology. You will need to troubleshoot the problem by issuing commands on the devices. To begin troubleshooting a ticket, click on the BLUE trouble ticket button on the right. 
For each ticket, you will be required to answer the following three questions:
Which of the following devices is the source of the problem? 
Which of the following technologies is the source of the problem? 
Which of the following is most likely to solve the problem? 
Although the ticket scenarios might look similar, the devices are configured differently for each ticket. You can access a device by clicking on its button at the bottom of the screen or by clicking on its picture in any of the topology diagrams. You can open the topology diagrams by clicking on the topology buttons at the bottom of the screen. You can have multiple devices and topology diagrams open at the same time. 
You can access the following devices for each trouble ticket:
R1, R2, R3, and R4: Cisco 2600s
R5: Cisco 3640
DS1 and DS2: Cisco Catalyst 3560s
AS1: Cisco Catalyst 2912XL
PC1: Windows-based client operating system
Not all commands are available on each device. Only certain show, ping, and traceroute commands are available on the routers and switches. Only the ping and ipconfig commands are available on PC1. You cannot access the ISP router or any of the servers. 
You can move among the three questions in the trouble ticket by clicking Previous Question and Next Question. After you have answered the third question, you can click Done to complete the trouble ticket. In study mode, you can complete a trouble ticket and display the explanation by clicking Done + Show Explanation. However, once you have clicked either of these two GREEN buttons, your responses will be recorded and the ticket button will turn RED. In simulation mode, you will be unable to reopen the ticket. 
Click the CLOSE button at the bottom right when you are ready to end the troubleshooting simulation. 
Layer 2 Topology 

• A: issuing the redistribute eigrp 1 metric 64 subnets route-map eigrp-to-ospf command in OSPF
• B: issuing the redistribute eigrp 1 metric 64 subnets route-map ospf-to-eigrp command in OSPF
• C: issuing the default-metric 1000 100 255 1 1500 command in EIGRP
• D: issuing the no redistribute static command in the OSPF 15 process
• E: issuing the redistribute ospf 15 route-map eigrp-to-ospf command in EIGRP
• F: issuing the redistribute ospf 15 route-map ospf-to-eigrp command in EIGRP

Correct Answer: C

You should issue the default-metric 1000 100 255 1 1500 command in Enhanced Interior Gateway Routing Protocol (EIGRP) on R3. To determine which device is the source of the problem, you should issue the ping and traceroute commands to test connectivity between devices. You can use any troubleshooting method you want, as long as you follow a systematic procedure. For example, you can ping from R5 to the closest device and work your way up the network until communication is lost, or you can ping from R5 to the farthest device and work your way back to R5 until pings are successful. Alternatively, you can trace from R5 to R1 and see where communication is lost along the path to the destination device.  
In this scenario, if you were to issue the traceroute 210.98.76.74 command from R5, you would receive the following partial output: 

   

The *** in the output indicates that the attempt to trace the IP address 210.98.76,54 timed out after the hop at IP address 192.168.1.9, which is the IP address assigned to the Serial1/0.324 subinterface on R3. All routers above R3 are able to ping and trace to 210.98.76.54. Additionally, if you were to issue the traceroute 10.10.22.31 command from R2, you would receive the following partial output:

   

The !H !H !H in the output above indicates that the host at IP address 10.10.22.31, which is the IP address assigned to PC1 by the Dynamic Host Configuration Protocol (DHCP) server on R5, is unreachable, although there is a route available to that host. The trace reports that the host is unreachable after the IP address 123.45.67.90, which indicates that R2 is attempting to access 10.10.22.31 by a route out R1 and through the public network rather than through R3, which is the correct route to PC1. Because R2 cannot ping or trace below R3 and because R5 cannot ping and trace above R3, the most likely point of connectivity loss in the network is R3, even though R3 can ping and trace to both sides of the network.  
Once you have determined where connectivity is lost, you can begin to troubleshoot the cause of the problem. There are two routing protocols that are operating at the Network layer of the OSI model on R3: EIGRP and Open Shortest Path First (OSPF). To determine which protocol is most likely causing the problem, you should verify the configuration and operation of each protocol. If you were to issue the show ip route command on R3, you would receive the following output: 

   

The output above indicates that all subnets in the network are accounted for on R3. Two subnets are directly connected routes. Three subnets above R3, including the default 0.0.0.0/0 route, are routed by EIGRP process 1. Nine subnets below R3 are routed by OSPF process 15. Because all of the networks connected to R3 are accounted for in the routing table and are segregated by the EIGRP and OSF boundaries on R3, you should ensure that routing redistribution between EIGRP process 1 and OSPF process 15 is correctly configured.  
If you were to issue the show running-config command on R3, you would receive the following partial output: 

   

   

In the output above, the EIGRP 1 routing proves has been configured to redistribute routes from the OSPF 15 process based on permit and deny rules found in a route map named ospf-to-eigrp. Similarly, the OSPF 15 routing process has been configured to redistribute routed from the EIGRP 1 process based on information in a route map named eigrp-to-ospf. The difference between two configurations is that the OSPF process has defined a seed metric of 64 in the redistribute eigrp command and the EIGRP process has no seed metric. Routing protocols differ in the types of metrics they use to route traffic. As a result, a seed metric is required in order to inform one protocol of the metric necessary to redistribute routing information from the other protocol. Seed metrics can be defined by issuing the default-metric command in the routing process configuration, by issuing the metric keyword in the redistribution command, or by configuring a route map. The route map in this scenario do not provide seed metrics, and no metric keyword has been issued for the redistribute eigrp command. Therefore, issuing the default-metric 1000 100 255 1 1500 command in the EIGRP 1 routing process configuration would solve the problem.  
You should not issue the redistribute eigrp 1 metric 64 subnets route-map eigrp-to-ospf command or the redistribute eigrp 1 metric 64 subnets route-map ospf-to-eigrp command in OSPF on R3. There are two route maps configured on R3, eigrp-to-ospf and ospf-to-eigrp. The eigrp-to-ospf route map applies to routes from EIGRP process 1 that are redistributed into OSPF process 15. The ospf-to-eigrp route map applies to routes from OSPF process 15 that are redistributed into EIGRP process 1. In this scenario, the route maps are already correctly assigned to the appropriate redistribute command.  
You need not issue the no redistribute static command on any device. Although the redistribute static command is not necessary on R3, because there are no static routes defined on R3, issuing the no redistribute static command would not fix the redistribution problem between EIGRP and OSPF on R3.  
You should not issue the redistribute ospf 15 route-map eigrp-to-ospf command or the redistribute ospf 15 route-map ospf-to-eigrp command in EIGRP on R3. Modifying the route map assignments in this scenario would not fix redistribution between EIGRP and OSPF, because the route maps are already correctly assigned to the appropriate redistribute command.  
Reference: 
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_eigrp/command/ire-cr-book/ire-a1.html#wp3025014087

Instructions  
This item contains a trouble ticket covering a single network topology. You will need to troubleshoot the problem by issuing commands on the devices. To begin troubleshooting a ticket, click on the BLUE trouble ticket button on the right. 
For each ticket, you will be required to answer the following three questions:
Which of the following devices is the source of the problem? 
Which of the following technologies is the source of the problem? 
Which of the following is most likely to solve the problem? 
Although the ticket scenarios might look similar, the devices are configured differently for each ticket. You can access a device by clicking on its button at the bottom of the screen or by clicking on its picture in any of the topology diagrams. You can open the topology diagrams by clicking on the topology buttons at the bottom of the screen. You can have multiple devices and topology diagrams open at the same time. 
You can access the following devices for each trouble ticket:
R1, R2, R3, and R4: Cisco 2600s
R5: Cisco 3640
DS1 and DS2: Cisco Catalyst 3560s
AS1: Cisco Catalyst 2912XL
PC1: Windows-based client operating system
Not all commands are available on each device. Only certain show, ping, and traceroute commands are available on the routers and switches. Only the ping and ipconfig commands are available on PC1. You cannot access the ISP router or any of the servers. 
You can move among the three questions in the trouble ticket by clicking Previous Question and Next Question. After you have answered the third question, you can click Done to complete the trouble ticket. In study mode, you can complete a trouble ticket and display the explanation by clicking Done + Show Explanation. However, once you have clicked either of these two GREEN buttons, your responses will be recorded and the ticket button will turn RED. In simulation mode, you will be unable to reopen the ticket. 
Click the CLOSE button at the bottom right when you are ready to end the troubleshooting simulation. 
Layer 2 Topology 

• A: R1
• B: R2
• C: R3
• D: R4
• E: R5
• F: DS1
• G: DS2
• H: AS1

Correct Answer: E