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642-832 Exam Guide
No filler. No hype. Exam-focused.
“A portable, comprehensive guide with everything you need to get up to speed and pass the TSHOOT Exam - the first time.”

The Online

I started as a way for me to capture technical notes as I prepared for the three major CCNP Exams – SWITCH, ROUTE, & TSHOOT. As I began sharing my notes with the world, I immediately started to receive feedback on the three exam’s focus areas and how difficult they had become. What I realized was that the exam prep resources available (read: Cisco Press Books) were not even covering all of the exam topics, including some that you were required to configure in live simulation scenarios. First-time fail rates seemed normal and a big part of that was because the some of the simulation scenarios required you to know some extremely specific protocol configuration details that most network professionals just wouldn’t know off the top of their heads. I began to tailor my notes to include topics that were not being covered in “official” exam guides and trimmed down those that just were not necessary. The feedback was overwhelmingly positive from the online community! The problem is, of course, that the notes were not formatted well for off-line consumption and didn’t include enough lab/scenario-based examples. This guide is an answer to the countless requests to create a portable, comprehensive, and exam-focused TSHOOT prep guide. I’ve refined the online notes even more to focus exclusively on exactly what you Cisco expects you to know on exam day. If you have questions, exam feedback, or want to reach out to me directly - shoot me an email at I promise you’ll get a response.

Best of luck.


Network Maintenance The Art of Troubleshooting Layer 2 Troubleshooting Layer 3 Troubleshooting TSHOOT Exam Methodology

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Cisco Chapter 1:

Network 642 Maintenance 832

but it is important as a network engineer to understand what models exist and how they translate into improving your organization. Many organizations use parts of several instead of adopting one method completely. Note that ITIL is a large and comprehensive approach that was developed specifically for IT professionals. Good troubleshooting reduces the time an outage lasts.Maintenance is no doubt an important component to network stability and that's why we see it covered on the troubleshooting exam. Maintenance Methodologies Several well known maintenance models have been defined by a number of organizations. This is perfect multiple-choice style content as it is difficult to test your understanding of maintenance concepts and methodologies on a simulation-focused exam like TSHOOT. Keep that in mind as you walk through the following topics. 5|Page . good maintenance minimizes outages themselves. IT Infrastructure Library (ITIL) ITIL focuses on creating a technology service framework within an organization and aligning it closely with the organization's requirements and processes. A documented maintenance strategy is worth its weight in gold.

availability (CIA) ■ Authentication. Plan. integrity. sometimes also referred to as PPDIOO. authorization. This model is specifically focused on deploying and operating Cisco's product families. Fault management ■ Preventive maintenance Configuration management ■ Both hardware and software installation and configuration ■ Change control ■ Inventory management Accounting management ■ Capacity planning ■ Cost efficiency Performance management ■ Maximize performance on existing network investments Security management ■ Confidentiality. accounting (AAA) ■ Encryption ■ Intrusion detection/prevention ■ Minimizing network downtime Cisco Lifecycle Services Cisco has come up with their own maintenance model.FCAPS FCAPS is an IT maintenance model created by ISO that categorizes network management into five parts. Implement. FCAPS is an acronym using the first letters of the five categories it includes. Design. and Optimize. 6|Page . or Prepare. Operate.

etc. After all. FTP could be used for configuration backups for example. Once the model has been selected. moves. tools should be selected to carry out those processes.). there are some functions that should be included every time. and changes ■ Installing and configuring new network devices ■ Replacing failed hardware ■ Software backup ■ Configuration backup ■ Troubleshooting failure scenarios ■ Software upgrades ■ Network performance monitoring ■ Capacity planning ■ Creating/updating network documentation 7|Page . After the maintenance model components have defined an organizational processes (ex. automated config backups. manual security audits. These include: ■ Managing adds. Network Maintenance Core Tasks Whatever model an IT organization chooses.Telecommunications Management Network (TMN) TMN was developed by ITU-T and is a tailored version of FCAPS specific to the telecommunications industry. its parts should inform an IT organization's processes and standard procedures. a model is meaningless unless it affects how a business operates.

TFTP and FTP servers are available on all modern operating systems and free.Documentation Up-to-date. and complete infrastructure documentation is crucial to reduce recovery times and maintain a robust networked environment. One of the simplest methods is to save the configuration as a text file on a remote TFTP or FTP server. etc. or snapshot. clear. support info. This is a tremendous help during troubleshooting efforts because without knowing what normal levels are. Adding the date to the saved configuration can make rolling back changes easier in the future. but some common details that should be documented include: ■ Production configurations ■ Inventory (including serial numbers.) ■ Circuit information ■ Network drawings ■ IP address assignments Another important component to network documentation is a performance baseline. and port status. WAN jitter and delay. It captures the expected performance of your network systems like link bandwidth. open source offerings are widely available. detecting abnormal traffic behavior becomes very subjective. IOS Tools Configuration Configurations should be backed up periodically or after changes are made. Different levels of detail are appropriate for different audiences. Here's an example of a router saving it's configuration to a local TFTP server: 8|Page .

Know that every syslog message contains two parts. a severity level and a facility. Syslog Priority (highest to lowest): 0. Error 4. Alert 2.RouterA# copy run tftp Address of name of remote host []? 10. Obviously. Critical 3. The severity level goes from 0 to 7 with 0 being the most severe to 7 being simply informational. Emergency (highest) 1. Informational 7.35 Destination filename [routera-config]? Routera_config_02082012 Syslog Syslog is a tool that collects alerts from network devices and stores them on a common log. Notice 6.10. Warning 5.1. this can be very handy when you need to troubleshoot an issue across many devices. Debug (lowest) 9|Page .

Make sure you have it consistent (ex. The archive function maintains a copy of the current configuration as well as a set of past configurations. Stratum 1 clocks are synchronized directly with an atomic clock. called archive. local time zones. it is important to consider the time zone that each device is set to. GMT. NTP stands for Network Time Protocol and is used to keep accurate and consistent time on all network devices. HQ time zones. etc) Archive Cisco has developed a built-in configuration backup and restore feature. but if the timestamps that are included are off then the alerts are unreliable (and next to useless). which is assigned by stratum. If a configuration change is made with unpleasant results. the switch or router can roll back to a previous configuration relatively easily. stratum 2 clocks get their time from stratum 1 clocks. Configuring NTP is easy .just point the device to the proper time server: Switch(config)# ntp server ip_address_of_ntp_server To verify: Switch# show ntp status One last note for NTP. There are several keywords available inside archive configuration mode. NTP works by pulling the current time from a time server.NTP Alerting is important. etc. Here is a list of some of the most common: 10 | P a g e .

tftp server. etc. When the archive function backs up a configuration. Time-period Sets the maximum time allowed before another backup is automatically saved. It will count up to 14 (represented as filename-14) and then cycle back to 1.txt Write-memory When the write-memory keyword is configured.1. then you're backups may be written over too often.168. 11 | P a g e . If your time-period is set too frequently. -3. it appends a -1. -2.Path Specifies where you want the backup configuration stored (ex. a backup of the configuration will be automatically saved every time the configuration is manually saved. etc. to the end of the file name depending on how many have already been saved.22/routerc. flash.). Examples: archive path flash://routerc archive path tftp://192.

Cisco Chapter 3: 642 832 The Art of Troubleshooting 12 | P a g e .

There are several common structured troubleshooting approaches. The structured approach also is helpful when the hypothesis you create fails. checking each node/device/configuration along the way. with these being the most common: Bottom-Up Start with the OSI physical layer and work your way up. technique. The second part. There are a number of methods to tackle the same problem. To be honest. Spot-the-Difference This is where configurations are compared between what is currently running and what the expected configurations should be. 13 | P a g e . forming a hypothesis. The important part is that you are consistent and your troubleshooting methodology follows a structured approach. Preparation comes in the form of documentation. Top-Down Start with the OSI application layer and work your way down. The recovery time for a structured troubleshooting approach is usually much less than randomly changing configurations or settings in a hurry to try and get things working. Follow-the-Path Consider the path a packet would take from source to destination. and understanding of the environment among other things. change control. and then testing it.There are two elements to good troubleshooting . is just as important. Move-the-Problem Move a device to see if the problem moves with it. Structured Troubleshooting What Cisco calls structured troubleshooting simply means you use a system to solve a problem by collecting information about the problem. It may rule out many more scenarios and likely leads to the next hypothesis to test.preparation and technique. Cisco doesn't promote a specific approach for the CCNP TSHOOT exam.

When you find a test that is successful and determined that it in fact is the root cause. Keep in mind that you will need to understand that they are explaining the symptoms ." or "I can't get to my Facebook account when I should be processing TPS reports".Use the Scientific Method The first step whenever you encounter a technical problem is to define the problem. or whatever approach you are using.." or "my email is slow. What's the scope? How many users are affected? What changed? When did it happen? Is it a constant problem or intermittent? Now this is where your tool bag of structured troubleshooting methodologies should come out. This will involve collecting input from those experiencing the issue directly .. think about your current change control policy and ask if it needs to be updated. You get the idea..but they are rarely done consistently.. simple tasks . After you have identifies the problem. continue through the layers. These are small. Try one that you think best matches your hypothesis of the root issue and work your way through it. Did your test work? If not. it's time to trim it's your job to determine the problem behind the symptoms. the path.. make sure to communicate the problem and recovery to all stakeholders and update any necessary documentation..things like "the Internet is down. 14 | P a g e . If a configuration change was the culprit.

Cisco Chapter 3: 642 832 Layer 2 Troubleshooting 15 | P a g e .

Poor Switch Performance Most performance issues on switches are related to one of three errors: 1. Duplex mismatches between switch ports and an attached device 3. switch and server. Late-Col. 16 | P a g e . Undersize. Cisco recommends setting all interfaces. Multi-Col. Giants The transmitting NIC may have problems. Cabling and port problems (layer 1) 2. to auto. Excess-Col All of these are collision types. which can point to a duplex mismatch. TCAM issues. Physical layer Troubleshooting Commands #show interface # show interface counters # show interface counters errors Look for the following errors: FCS-Err Usually a cabling issue. Single-Col. This is sometimes seen when switching from a fast link to a slower one. Xmit-Err The transmission buffers are full.

current root bridge. and cost to that root bridge. there will be only one root bridge . To see the status of spanning tree: # show spanning-tree vlan vlan-id To view sent/received BPDU information for a switch: #show spanning-tree interface interface detail 17 | P a g e .also called a non-designated port. If the BPDU has a lower advertised root. If a switch receives two BPDUs with the same root.Spanning Tree Spanning Tree Protocol is a loop prevention mechanism to allow redundant Ethernet network connections. Each switch periodically transmits BPDUs that include its bridge ID. The port with the higher cost is blocked . 2. Additionally.with each non-root switch having only one root port. Link Speed Ethernet Fast Ethernet Gigabit Ethernet Ten Gigabit Ethernet STP Cost 100 19 4 2 After the whole process. To quickly review STP costs. 3. each switch starts by assuming it is the root bridge. If a switch receives a BPDU from another switch with a different root. The port that received the BPDU is now the root port . the switch changes its root to match and recalculates the cost to the new root. it then compares costs and uses the port with the lowest cost.all others become designated ports. below is a list of link costs based on interface speed. it does a comparison. Here is an important summary of how each switch determines Spanning Tree port roles: 1.

Both sides of the EtherChannel must be configured as a bundle directly or be using a link aggregation protocol (LACP or PAgP). duplex. If one side is configured as an EtherChannel and the other side is not. Every port participating in an EtherChannel must have identical speed.Broadcast Storms Broadcasts storms can occur due to Spanning Tree misconfigurations and/or rogue switches being added which closes a loop. Troubleshooting EtherChannels EtherChannel issues usually fall into one of three categories: 1. check each port configuration. look for error-disabled EtherChannel ports on the EtherChannel-enabled switch. 4. becomes unresponsive. If an EtherChannel isn't forming. so often times to fastest way to fix the problem is to physically begin pulling redundant links. 2. and all the links light up solid green. 18 | P a g e . The CLI may be very slow to respond if you still have remote access to it. Also note that link bundles should be used in even numbered pairs like 2. access or trunk settings. 3. Regardless. If traffic is only flowing over a single link in a bundle. 8. it is likely that the hash algorithm should be adjusted to use different seed values. etc. a broadcast storm will be obvious when the switch slows way down.

improper VTP mode. Switch Tables It is important that you understand what show commands display information on what switch tables.things like software bugs. These will come in handy when you are isolating a switching issue. or bad switch ports. and native VLAN mismatches. VLAN issues usually come in the form of misconfigured VLANs. or ARP problems. you should first make sure you have tested for physical layer issues like bad cabling. MAC Address Table [MAC-to-port mapping] # show mac-address VLAN Assignments [VLAN-to-port mapping] # show vlan Trunk Assignments # show interface switchport #show interface switchport trunk #show etherchannel 19 | P a g e . loops.VLANs When troubleshooting issues that you suspect are related to VLAN logic. a power failure. check that you are not dealing with an issue with the switch itself . Also. trunk issues.

and GLBP. show ip cef displays the CEF forwarding table and show adjacency will show you the layer 2 headers used in forwarding. Switches can either use MAC address forwarding (for layer 2 forwarding).SVIs will only go into down state when all interfaces within that particular VLAN are down. Keep in mind that routers always use layer 3 information to pass traffic between ports. HSRP. SVIs for inter-VLAN routing. Check out the High-Availability page to learn more. while still only showing a single gateway IP and MAC address. • • VRRP is another gateway redundancy protocol that is an open standard and very similar to HSRP. or a layer 3 switch but the data plane is different depending on the platform you are using. GLBP is Cisco proprietary. • • The three FHRPs Cisco supports are HSRP. VRRP. Either way. The last category. & GLBP • First hop redundancy protocols allow a layer 2 segment to have two gateway routers for redundancy. • Last thing to remember . One router is active and another is a backup (using HSRP keepalives to maintain connectivity). routed ports do not run layer 2 protocols like Spanning Tree – that’s very important. HSRP is extremely popular and you should make sure to understand how it works for the TSHOOT exam. or layer 3 routed ports. 20 | P a g e . HSRP is one of the original FHRPs that was developed by Cisco and is proprietary. its primary advantage is its ability to automatically load balance between gateway routers.Troubleshooting Inter-VLAN Routing • • • Routing between VLANs can be done on either a router. VRRP.

highest wins).1. Each HSRP-enabled router has a default HSRP priority of 100 (remember. Routers in the same HSRP group share a common MAC and virtual IP address. An example HSRP configuration could look something like: Router(config)# interface gig1/1 Router(config-if)# ip address 192.168. HSRP is configured using the standby command under interface configuration mode.HSRP HSRP is the primary FHRP covered on the TSHOOT exam. issue: # show standby # show standby brief 21 | P a g e . so let's go through the basics one more time.1.2 Router(config-if)# standby 4 ip 192.1 Router(config-if)# standby 4 priority 200 Router(config-if)# standby 4 preempt To show the current HSRP status. The standby configuration statements define the HSRP group as well as the virtual IP in use.168. If another router joins the group with a higher priority it will still not become the active router unless the preempt command is applied.

Cisco Chapter 4: 642 832 Layer 3 Troubleshooting 22 | P a g e .

The routing table pairs network prefixes with the router's preferred next hop address or interface. Packets are routed based on the output of the routing table by first matching the longest prefix and then using other IGP-specific metrics. After the router has determined what the next-hop address is. For further digging. The show ip arp command will display the current ARP pairings. CEF is used in layer 3 switches to optimize routing and layer 2 headers. AS numbers. the router then needs to translate that into a layer 2 MAC address. use the show ip cef command.). To view the CEF entries. look at the routing table to make sure a route to the destination exists. Finally. Next. First. The ARP table is exactly what this is for. and CEF mappings. Three tables are used: the routing table. etc.Routing Basics Before we get into the layer 3 troubleshooting methods. we first need to make sure we have a basic understanding of how routers and multilayer switches route traffic. the show ip protocols command gives some very helpful information on the current routing protocols in use (like timers. ARP table. 23 | P a g e . The show ip route command displays the contents of the routing table. Troubleshooting Any Routing Protocol Regardless of what routing protocols are in use. run a traceroute from the source towards the destination to see where the last reachable hop is. there are some common troubleshooting steps that can be applied. try to ping the destination to determine reachability. Lastly.

Step 1 Is the route being advertised correctly? Step 2 Is the route being received? Step 3 Is there a more desirable route being used? (longer prefix or lower administrative distance) Let's dissect each of these for the major routing protocols one at a time.regardless if you are running EIGRP. and topology table. or BGP. EIGRP First. verify connectivity to the remote networks using pings and by taking a look at the local routing table. OSPF.Routing Protocol Troubleshooting Methodology There are three key questions that can be extremely helpful when troubleshooting a routing issue . As a reminder. 24 | P a g e . neighbor table. EIGRP stores its information in three different tables: the EIGRP interface table.

There are two simple ways to check if that router is advertising the routes properly.EIGRP Interface Table The EIGRP interface table displays interfaces participating in the local EIGRP processes. First. Is the EIGRP route being advertised properly? Remember those three troubleshooting questions listed above? Let's start with the first one . and that any authentication configurations are the same. Remember. EIGRP only advertises subnets of interfaces that match an EIGRP network statement. Another option is to do a show ip the route being advertised properly? The first step is to identify the router that is connected to the destination subnet as it should be advertising the route out. You should see the neighbor listed on each device. including what networks are being advertised with the network statements. To check this. The nice thing about this command is that it displays the EIGRP network statements. Use the show ip eigrp interface command to display its contents. Use the show ip eigrp neighbors command to display its contents. This will display the running EIGRP configuration. issue a show ip eigrp neighbors on the two routers exchanging hellos. Is the EIGRP route being received? Routers must be EIGRP neighbors for the routing information to be shared. EIGRP Topology Table The topology table contains a complete list of EIGRP-learned routes. do a show run | section eigrp. Use the show ip eigrp topology command to display its contents. If all of that looks good. look at the EIGRP running configuration and make sure the AS numbers match. You can also perform a debug ip eigrp packets to make sure hellos are being sent out from each router. EIGRP Neighbor Table The EIGRP neighbor table contains a list of discovered EIGRP neighbors. the timers are close. 25 | P a g e .

Compare the EIGRP topology table to the local routing table. that will be used instead. but it is not being used in the routing table. Do a show ip protocols to display any distribute lists. Use the show ip ospf database command to display its contents. If a more desirable path is known. Lastly. neighbor table. Use the show ip ospf neighbors command to display its contents. route maps or distribution lists could be blocking routing traffic. OSPF stores its information in three different tables: the OSPF interface table. OSPF Link State Database The link state database contains the received LSAs.Next. OSPF Neighbor Table The neighbor table contains a list of discovered OSPF neighbors. and link-state database. First. issue a show ip eigrp interface to make sure the interfaces you expect are participating in the EIGRP process. verify that there is a problem using pings and by taking a look at the routing table. Is there a more desirable route being used? It's possible that EIGRP knows about the route. 26 | P a g e . OSPF These steps for troubleshooting OSPF are very similar to EIGRP. Use the show ip ospf interface command to display its contents. OSPF Interface Table The OSPF interface table displays interfaces participating in the local OSPF processes.

route maps or distribution lists could be blocking routing traffic. OSPF requires that all of the following parameters match between devices: ■ Bidirectional communication ■ AS number ■ Timers ■ Common area type ■ Common subnet prefix ■ Authentication The OSPF protocol values can be seen using the show ip ospf interfaces command. OSPF only advertises subnets of interfaces that match an OSPF network statement. To check this. You can also perform a debug ip ospf adj to show any issues that would prevent the routers from forming an adjacency. OSPF is more particular about matching protocol variables than EIGRP. There are two simple ways to check if that router is advertising the routes properly. 27 | P a g e . Is the OSPF route being received? Routers must be OSPF neighbors for the routing information to be shared. issue a show ip ospf neighbors on the two routers. You should see the neighbor listed on each device. Remember. This will display the running OSPF configuration. First. Lastly.Is the OSPF route being advertised properly? The first step is to identify the router that is connected to the destination subnet as it should be advertising the route out. Another option is to do a show ip protocols. including what networks are being advertised with the network statements. do a show run | section ospf. Do a show ip protocols to display any distribute lists.

If you need to investigate further. it also shows the BGP best path to each destination.Is there a more desirable route being used? It's possible that OSPF knows about the route. Use the show ip bgp command to display its contents. a debug ip bgp updates should show the BGP hellos and advertisements. make sure they have L3 connectivity using a simple ping test. Are the BGP routers neighbors? BGP neighbors must be administratively assigned on each router running BGP. BGP Neighbor Table The neighbor tables contains a list of known BGP neighbors. Use the show ip bgp neighbors command to display its contents. If a more desirable path is known. If the expected BGP peers do not show up in the output. Perhaps most importantly. BGP BGP stores its information in two tables: the BGP neighbor table and the BGP table. but it is not being used in the routing table. Compare the OSPF topology table to the local routing table. Take the time to check each hop along the expected path and look at the routing tables on each router. BGP routing and network information will not be passed between them. that will be used instead. 28 | P a g e . Start by doing a show ip bgp neighbors. BGP Table This table contains all the received BGP prefixes as well as their associated attributes lists. If the routers are not neighbors.

it will not work. If the redistributing router does not have a routing table entry for the route being redistributed. Route Redistribution Route redistribution can be a tricky situation to troubleshoot. There are two simple ways to check if that router is advertising the routes properly. Understand that redistributed routes lose their native metric information. 1.Remember that BGP requires bidirectional communication as well as matching AS numbers and authentication. but understanding the following concepts should be helpful. Routing loops are a common problem with multi-router routing redistribution. Also. 2. make sure that the router connected to the destination subnet is advertising the route out. Redistributed routes require an existing entry in the routing table. When redistributing into EIGRP. but it should checked right away. Do a show ip protocols to display any distribute lists. When redistributing into OSPF. 29 | P a g e . The show run or show ip bgp command will display that information. a default metric MUST be set or no route will be imported. You should also keep in mind that BGP will only advertise routes when (1) they are defined using neighbor statements and (2) the router knows about the route from another source. all routes will be imported as classful unless the subnets keyword is appended to the end of the redistribution statement. 3. Use a single router to perform the redistribution if possible. Seems simple. Is the BGP route being advertised? As with the other routing protocols. consider that route maps or distribution lists could be blocking routing traffic. Perform a show run | section bgp to look at the neighbor statements.

so it is crucial to go into the test with a troubleshooting methodology that you are comfortable with. so take the time to understand the material but realize that the majority of your time should be spent going through the trouble ticket methodology I present below. Let me warn you though. they published the topology diagrams – complete with IP and interface information to those who are interested in reviewing it before the exam. Cisco really focuses on the content that you’ll find here under the Network Maintenance and Art of Troubleshooting chapters. because the testing style is such a huge departure from Cisco’s traditional certification exams. you need to have a plan of attack when you walk into this exam or it won’t turn out well for you. In fact. This allows Cisco to make sure you understand how to troubleshoot every device and protocol between the client and server. The Multiple Choice Section Before we go too far into the Trouble Ticket portion of the exam. To test your troubleshooting. Most of the trouble tickets explain the symptoms in terms of a client not being able to ping/access/connect to a server on the other end of the topology. 30 | P a g e . Cisco uses trouble tickets – each with a general description of a problem with a source and destination device. That’s exactly what we’ll do in just a moment. While this may seem daunting. That’s by far the most difficult part of the exam and the section you should focus your time on most. let me just say a few words about the multiple choice section. Also. the problem descriptions can be very vague and exactly the same as other tickets. You need to REALLY read those two chapters before heading into the exam. which require you to identify the source of a network connectivity issue. I think the best way to prepare is to go through some practice questions using the actual exam topology to get you comfortable with the layout and question types. knowing this before you head into the exam allows you to have a strategy and a starting point for every ticket you troubleshoot. I’ve done you a favor by including the diagrams for you below. Realize that there are only going to be a few multiple choice questions.TSHOOT Exam Details The TSHOOT exam consist of a few multiple choice questions and a long list of trouble tickets. The topics in those chapters are mostly about maintenance methodologies and troubleshooting methods and Cisco expects you to be familiar with the terms used. Lastly.

That means that it is likely a layer 2 connectivity issue on the connected access switch ASW1. the second asks what protocol or technology it is related to.x range. Knowing this.x address.1.Solving the Trouble Tickets Each ticket presented to you will have three questions you must answer. make some notes. All of the problem descriptions begin with Client X cannot connect to Destination Y. like 10. 31 | P a g e . Here’s the trick: Start each ticket by perform an ipconfig inside client 1’s terminal. Run the command ipconfig. the distribution switch DSW1. open ticket #1 and jump onto the client’s terminal. Now.4 or give you an unusable IP address in the 169.x. Doing that allows you to see the problem. It will save you tons of time and frustration because it allows you to very quickly localize the problem.x. but it is incredibly important to understand that at any point when you have a trouble ticket open you can select the abort button on the ticket to back out. then back out and do the same for the next ticket.x. or a DHCP-related issue on the local router (R4 in this case). Trouble Ticket Methodology Now here’s where we get down to business. The first asks what device is causing the issue. it may not seem obvious when you are taking the test. If the client has a 169. do some quick testing to see if it is layer 2 or layer 3 issue. but I highly recommend taking my advice on how to approach the tickets. then it is not getting a proper IP address from the local DHCP server. You are welcome to use any troubleshooting methodology you like. The IP address of Client 1 will very quickly narrow close to half of the tickets for you. and the third question asks what specific configuration should be applied to resolve the issue.x. The output will either give you a usable IP address.2.

Check for port security applied to the interface connected to the client (fa1/0/1) ASW1#show int fa1/0/1 (FastEthernet1/0/1 is down. Verify that the interface connected to the client (fa1/0/1) is up. and is assigned to the proper VLAN.x.ASW1#show run interface fa1/0/1 (Look for switchport access vlan 10) 2.If Client 1 has an IP address of 169. ASW1#show etherchannel summary (Look for po13) DSW1#show etherchannel summary (Look for po13) 32 | P a g e .x 1. running in access mode (not a trunk).x. Verify that the PortChannel interfaces in PortChannel are up and participating in the bundle. 3. To check that the interface is in up/up status – ASW1#show int fa1/0/1 To check that it configured for access mode – ASW1#show run interface fa1/0/1 To check the port’s VLAN assignment . line protocol is down (err-disabled) will show up in the first line) To resolve this. the port security configuration would need to be removed from ASW1 and fa 1/0/1 would require a shut/no shut.

Check any DHCP-related issues on the distribution switch. In the scenario that Cisco provides here. 33 | P a g e . If one exists.x x.2. the normal “dhcp pool” and network statements should be verified. Another very important statement to look out for is a “ip dhcp excluded-address x.x. Some production networks run DHCP servers on their local distribution switches to avoid the headaches of a dedicated.4 (Client 1’s IP) – it is a problem and will block Client 1 from obtaining an IP address.4. physical DHCP server. only the 10. use the following “sh run” commands to pinpoint the configuration error. DSW1 to make sure the production VLANs are not being filtered on the trunk interface.1.2.2 addresses should be included in any excluded-address statements. If any other excluded-address range is configured on DSW1 and contains 10. Check the trunk link between the access switch. 5. ASW1 and the local distribution switch.2. Both addresses are the VLAN 10 interface IPs. Take a look at DSW1 for any DHCP server configurations. ASW1#show ASW1#show ASW1#show ASW1#show DSW1#show DSW1#show DSW1#show DSW1#show int run run run int run run run po13 trunk interface fa1/0/19 interface fa1/0/20 interface po13 po13 trunk interface fa1/0/19 interface fa1/0/20 interface po13 First do a show interface trunk to see what VLANs are “active” on the trunk.1 and 10.x. If VLAN 10 is not active based on the output.x.1. Doing so requires few devices and keeps DHCP services active at remote sites when the WAN goes down.x.1.x” statement. so they should not be included in any DHCP leases. In this example. there is likely IP address filtering going in somewhere on the local segment. Remember those VLAN Access-maps you learned about in the SWITCH exam? Well it may be the case that a VLAN access-map is dropping traffic on DSW1.x. the solution would be to remove the access-map completely.255 ! interface VLAN10 ip address 10.255.254 to check L3 connectivity to the distribution switch.1.1 255. Access-maps are generally configured like this: vlan access-map EXAMPLE 10 drop match ip address 5 ! vlan filter EXAMPLE vlan-list 10 ! ip access-list standard 5 permit 10.x AND can’t ping the gateway Ping the VLAN 10 default gateway address.If Client 1 has an IP address of 10. Because the client is getting a valid DHCP IP address from DSW1. 34 | P a g e .1.x.x/8 subnet.255.x. ping the DSW1’s VLAN 10 address to verify the client has layer three connectivity to the switch. there is L2 connectivity but something else is blocking (or dropping) the IP traffic from the client. If you see any VLAN 10 access-maps filtering the same subnet as Client 1.0 0.0. 10.255. ACL 5 and VLAN 10 access-map EXAMPLE are dropping all traffic from the entire 10.0. DSW1 From the client. If the ping fails.2.

Make sure the proper network statements are applied and that the correct AS number (10) is configured. R4 and DSW1 share routing information via EIGRP Autonomous System 10.x AND can ping the gateway on DSW1 BUT cannot ping the serial0/0/0/0.x. Remember that if either device is running an interface as passive.x.x AND can ping the gateway on DSW1 BUT cannot ping the fa0/1 interface of R4 The neighbor relationship between DSW1 and R4 needs to be checked.x. Do a show run on both devices and take a peek at the EIGRP configurations.x.If Client 1 has an IP address of 10. EIGRP hellos will not be sent and routes will not be shared. If you cannot connect to the other side of R4. the redistribution statements need to be looked at. If Client 1 has an IP address of 10.34 interface of R4 Notice that R4 is the redistribution point between EIGRP and OSPF. 35 | P a g e . Check for any EIGRP passive interface commands applied to the configurations.

252 ip nat inside ! router ospf 1 network 10. R1’s OSPF configuration should look something similar to: interface Serial0/0/0/ area 12 default-information originate If you see any OSPF authentication-related lines.x. If Client 1 has an IP address of 10.1. The OSPF configuration should be looked at carefully on both R1 and R2.Make sure a metric is set on the “redistribute ospf x metric” statement and that the subnets keyword id used on the “redistribute eigrp 10” statement.x. so we need to verify they are exchanging OSPF route information.1.1.0 0.255. If any route maps are applied to the redistribution configuration.1] If we can ping all the way from Client 1 to R2 but not to R1.x AND can ping the gateway AND can ping R2 [10.1. make sure they are applied exactly the same on both R1 and R2! An example interface authentication configuration: ip ospf authentication message-digest ip ospf message-digest-key 1 md5 EXAM 36 | P a g e .12 point-to-point ip address 10.1.2] BUT cannot ping R1 [10.1 255. Based on the diagram Cisco has made available. make sure the route map names are configured correctly.255.1. R1 and R2 share routes using OSPF.0. then there is an issue between routers R1 and R2.1.

R4 and DSW1 and DSW2 can also ping web server.2.1] Ping the webserver from R1 Successful.x. 37 | P a g e .1. Fails.x AND can ping the gateway AND can ping R1 [10. Check that the ‘inside’ and ‘outside’ NAT statements are applied to the correct interfaces on R1.x is included in the permit statements. make sure 10.x. If Client 1 can ping R1 and R1 can ping the web server. Also.1. This means that the issue is likely a NAT translation misconfiguration on R1.If Client 1 has an IP address of 10.x. R2. then R1. R3. check for any ACLs that NAT is using. If there are any.

2. 38 | P a g e .65. make sure they permit 209.0. R1 is using BGP to connect to the web server’s remote network.At this point we’ve established that Client 1 has connectivity to R1 BUT R1 does not have connectivity to the web server. Comb through the BGP configuration line-by-line. Again. The first item that needs to be verified is R1’s BGP configuration. If you run into any inbound ACLs on R1.65. this means we need to take a closer look at R1’s configuration. and AS numbers are correct.200. neighbor.224/30 network on R1. 1. so that is the first protocol to check.0. Make sure there are no ACLs blocking the remote 209.3.200. R1# show run Make sure the network.224 0.

Start by opening the first ticket presented to you and perform an ipconfig to determine Client 1’s IP address. so there’s not a lot of preplanning that will help you there besides reviewing the troubleshooting and methodology chapters at the beginning of this guide. If Client 1’s IP address is a 10.). Best of luck.x address.x. Next run through the list of common issues I noted for that particular situation.Final Exam Advice The exam starts with the multiple choice questions. etc.x address. You’ll likely find the answer with some careful observation fairly fast. walk through the ping tests I showed you in the previous pages.x.x. It’s helped many people pass the TSHOOT exam well under the allotted time. Access port VLAN. As you know by now the remainder of the exam involves solving a long list of trouble tickets. Here's what I would strongly recommend. 39 | P a g e . port security. trunk VLANs.x. begin troubleshooting the ticket based on the common issues I have presented above (ex. Doing so helps you determine which device is the cause. If it is a 169.

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