With this setting when that router reboots, it bypasses the startup-config and no password is required. What value should be displayed in Box 1 of the ipconfig output of host A? TCP segments are essentially datagrams.
TCP uses broadcast delivery. TCP provides sequence numbering of packets. TCP provides synchronized communication. TCP provides best effort delivery. The sequence number identifies the order of the bytes sent from each computer so that the data can be reconstructed in order, regardless of any fragmentation, disordering, or packet loss that may occur during.
Global id B. Public routable C. Summarization D. Unique prefix Correct Answer: D Explanation. Troubleshoot the network issues. Router R1 connects the main office to the internet, and routers R2 and R3 are internal routers.
NAT is enabled on router R1. R1 sends the default route into RIPv2 for the internal routers to forward internet traffic to R1. You have console access on R1, R2 and R3 devices. Use only show commands to troubleshoot the issues. Users complain that they are unable to reach internet sites. You are troubleshooting internet connectivity problem at main office. Which statement correctly identifies the problem on Router R1?
NAT configurations on the interfaces are incorrectly configured C. NAT translation statement incorrectly configured. Correct Answer: B Explanation. HSRP C. IP redirects C. RIB D. They are process switched.
Logging disables Cisco Express Forwarding. What does the address QUESTION 26 Scenario:You work for a company that provides managed network services, and of your real estate clients running a small office is experiencing network issues, Troubleshoot the network issues.
R1 sends default route into RIPv2 for internal routers to forward internet traffic to R1. A test-preparation routine proven to help you pass the exams. Chapter-ending and part-ending exercises, which help you drill on key concepts you must know thoroughly. Troubleshooting sections, which help you master the complex scenarios you will face on the exam. The powerful Pearson IT Certification Practice Test software, complete with hundreds of well-reviewed, exam-realistic questions, customization options, and detailed performance reports.
Links to a series of hands-on config labs developed by the author. Online, interactive practice exercises that help you hone your knowledge. More than 90 minutes of video mentoring from the author. A final preparation chapter, which guides you through tools and resources to help you craft your review and test-taking strategies.
Study plan suggestions and templates to help you organize and optimize your study time Well regarded for its level of detail, study plans, assessment features, challenging review questions and exercises, video instruction, and hands-on labs, this official study guide helps you master the concepts and techniques that ensure your exam success. Syslog message logging for device monitoring.
Skills and knowledge of device management related to backup and restoring device configurations, IOS feature licensing, and configuring time zones. With the products Cisco pdf for training and preparation of testing you would not only significantly reduce your fees, but pass your Cisco pdf exam.
We obtain our products from Authorities experts from test center. Thankfully, you do not have to decide now. At that point, you can make a better decision about which path works better for you. The only question is when to read each part of the two books.
The first option is pretty obvious, but the second one is less obvious. However, for those of you with a large amount of experience already, this alternate reading plan may work well. You can do these tasks now or do them in your spare moments when you need a study break during the first few chapters of the book.
But do these early. That way, if you do stumble upon an installation problem, you have time to work through it before you need a particular tool. Register for free , join the groups, and set up an email filter to redirect the messages to a separate folder. Even if you do not spend time reading all the posts yet, later, when you have time to read, you can browse through the posts to find interesting topics or just search the posts from the CLN website.
Also find my blog site as listed in the Introduction, and bookmark the pages that list the config labs, to have those handy for later study. Getting Started: Now Now dive in to your first of many short, manageable tasks: reading the relatively short Chapter 1. While learning those concepts, it helps to keep things as simple as possible. One way this book has kept the discussion simpler so far was to show examples that use one mask only inside a single Class A, B, or C network.
This chapter removes that restriction by introducing variable-length subnet masks VLSM. VLSM simply means that the subnet design uses more than one mask in the same classful network. VLSM has some advantages and disadvantages, but when learning, the main chal- lenge is that a subnetting design that uses VLSM requires more math, and it requires that you think about some other issues as well. This chapter walks you through the concepts, the issues, and the math.
Which of the following routing protocols support VLSM? Choose three answers. RIPv1 b. RIPv2 c. EIGRP d. What does the acronym VLSM stand for? Variable-length subnet mask b. Very long subnet mask c. Vociferous longitudinal subnet mask d.
Vector-length subnet mask e. Vector loop subnet mask 3. Which of the following subnets, when configured on another interface on R1, would not be considered an overlapping VLSM subnet? R4 has a connected route for Which of the following answers lists a subnet that overlaps with this subnet? A design already includes subnets All subnets are of Class A network However, Class A network In that case, the design does not use VLSM. VLSM provides many benefits for real networks, mainly related to how you allocate and use your IP address space.
Because a mask defines the size of the subnet the number of host addresses in the subnet , VLSM allows engineers to better match the need for addresses with the size of the subnet. For example, for subnets that need fewer addresses, the engineer uses a mask with fewer host bits, so the subnet has fewer host IP addresses. This flexibility reduces the number of wasted IP addresses in each subnet. By wasting fewer addresses, more space remains to allocate more subnets.
VLSM can be helpful for both public and private IP addresses, but the benefits are more dramatic with public networks. With public networks, the address savings help engineers avoid having to obtain another registered IP network number from regional IP address assignment authorities.
With private networks, as defined in RFC , running out of addresses is not as big a negative, because you can always grab another private network from RFC if you run out. To support VLSM, the routing protocol must advertise the mask along with each subnet. Without mask information, the router receiving the update would be confused. Is that subnet The dotted-decimal number To effectively support VLSM, the routing protocol needs to advertise the correct mask along with each subnet so that the receiving router knows the exact subnet that is being advertised.
By definition, classless routing protocols advertise the mask with each advertised route, and classful routing protocols do not. The classless routing protocols, as noted in Table , are the newer, more advanced routing protocols. Not only do these more advanced classless routing protocols support VLSM, but they also support manual route summariza- tion, which allows a routing protocol to advertise one route for a larger subnet instead of multiple routes for smaller subnets.
There is no command to enable or disable the fact that classless routing protocols include the mask with each route. The only configuration choice you must make is to use a classless routing protocol. From a configuration perspective, VLSM is simply a side effect of using the ip address interface subcommand. Routers collectively configure VLSM by virtue of having IP addresses in the same classful network but with different masks. For example, Example shows two of the interfaces from router Yosemite from Figure This command lists routes in groups, by classful network, so that you see all the subnets of a single Class A, B, or C network all in a row.
Legend omitted for brevity So ends the discussion of VLSM as an end to itself. This chapter is devoted to VLSM, but it took a mere three to four pages to fully describe it. Why the entire VLSM chapter? To do these same tasks on the exam requires skill and practice. As a result, hosts in different locations can be assigned the same IP address. Routers clearly cannot route packets correctly in these cases.
In short, a design that uses overlapping subnets is considered to be an incorrect design and should not be used. It then gets into an operational and troubleshooting approach to the topic, by looking at existing designs and trying to find any existing overlaps. For example, consider a subnet plan for Class B network If you use the math and processes to find all subnet IDs per Chapter 21, all those subnet IDs happen to have binary 0s in the host fields.
To begin, you would decide that you need some subnets with one mask, other subnets with another mask, and so on, to meet the requirements for different sizes of different subnets.
You might develop then a planning diagram, or at least draw the ideas, with something like Figure As soon as you choose to use one subnet from any column, you remove some subnets from the other lists because subnets cannot over- lap. Overlapping subnets are subnets whose range of addresses include some of the same addresses.
However, it shows a check mark beside two subnets that have been allocated for use; that is, on paper, the person making the subnetting plan has decided to use these two subnets somewhere in the network.
The subnets with a dark gray shading and an X in them can no longer be used because they have some overlapping addresses with the subnets that have check marks That subnet includes addresses from the subnet ID of As you can see just by looking at the subnet IDs to the right, all the sub- nets referenced with the arrowed lines are within that same range of addresses.
Now look to the upper right of the figure, to subnet The subnet has a range of That sub- net overlaps with the two subnets referenced to the left.
For instance, subnet But because there is some overlap, once the design has allocated the If overlapping subnets are implemented, routing problems occur and some hosts simply cannot communicate outside their subnets.
These address overlaps are easier to see when not using VLSM. With VLSM, overlapped subnets may not have the same subnet ID, as was the case in this most recent example with the subnets across the top of Figure To find these overlaps, you have to look at the entire range of addresses in each subnet, from subnet ID to subnet broadcast address, and compare the range to the other subnets in the design.
It uses a single Class B network This type of question might simply tell you that some hosts cannot ping each other, or it might not even mention that the root cause could be that some of the subnets overlap. To answer such a question, you could follow this sim- ple but possibly laborious process: Step 1.
Calculate the subnet ID and subnet broadcast address of each subnet, which gives you the range of addresses in that subnet. List the subnet IDs in numerical order along with their subnet broadcast addresses.
Scan the list from top to bottom, comparing each pair of adjacent entries, to see whether their range of addresses overlaps. For example, Table completes the first two steps based on Figure , listing the sub- net IDs and subnet broadcast addresses, in numerical order based on the subnet IDs.
As for the process, Step 3 states the somewhat obvious step of com- paring the address ranges to see whether any overlaps occur. Note that, in this case, none of the subnet numbers are identical, but two entries highlighted do overlap. The design is invalid because of the overlap, and one of these two subnets would need to be changed.
As far as the three-step process works, note that if two adjacent entries in the list overlap, compare three entries at the next step.
The two subnets already marked as overlapped can overlap with the next subnet in the list. For example, the three subnets in the following list overlap in that the first subnet overlaps with the second and third subnets in the list.
To that end, Table lists three practice problems. Just start with the five IP addresses listed in a single column, and then follow the three-step process outlined in the previous section to find any VLSM overlaps. In other words, you need to pick a new subnet and not make a mistake! For example, consider the internetwork shown earlier in Figure , with classful network So, you really have a couple of tasks: To find all the subnet IDs that could be used, rule out the ones that would cause an overlap, and then check to see whether the question guides you to pick either the numerically lowest or highest subnet ID.
This list outlines the spe- cific steps: Step 1. Pick the subnet mask prefix length for the new subnet, based on the design requirements if not already listed as part of the question. Calculate all possible subnet numbers of the classful network using the mask from Step 1, along with the subnet broadcast addresses. Make a list of existing subnet IDs and matching subnet broadcast addresses. Compare the existing subnets to the candidate new subnets to rule out overlap- ping new subnets.
Choose the new subnet ID from the remaining subnets identified at Step 4, paying attention to whether the question asks for the numerically lowest or numerically highest subnet ID. In this case, you need to add a new subnet to sup- port hosts. Imagine that the question tells you to use the smallest subnet least number of hosts to meet that requirement. For Step 2, you need to list all the subnet numbers and broadcast 22 addresses of You will not use all these subnets, but you need the list for comparison to the existing subnets.
Table summarizes that information, including the locations, subnet numbers, and subnet broadcast addresses.
Simply compare the range of numbers for the subnets in the previous two tables. In this case, the second through fifth subnets in Table overlap, so rule those out as candi- dates to be used. Table denotes those subnets with gray highlights. Step 5 has more to do with the exam than with real network design, but it is still worth list- ing as a separate step. Multiple-choice questions sometimes need to force you into a single answer, and asking for the numerically lowest or highest subnet does that.
This particular example asks for the numerically lowest subnet number, which in this case is NOTE The answer, For the exam, the zero subnet should be avoided if a the question implies the use of classful routing protocols or b the routers are configured with the no ip subnet-zero global configuration command.
Otherwise, assume that the zero subnet can be used. Chapter Review One key to doing well on the exams is to perform repetitive spaced review sessions. Table outlines the key review elements and where you can find them.
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