Question 1

You want to monitor Network Address Translation activity on a Cisco router as it happens. Which command will show real time NAT translations and activity messages rather than just the current translation table?

Accepted Answer

Introduction / Context: Network Address Translation, or NAT, is widely used to map private inside addresses to public global addresses. When troubleshooting NAT issues, you often need more than a static snapshot of the translation table. Real time debugging messages can show when translations are created, used and removed. Cisco IOS provides several show commands related to NAT and also debug commands that print detailed messages to the console. Given Data / Assumptions: You are working on a Cisco router that is performing NAT. You want to see live activity as packets are translated, not just the existing table entries. You understand that debug commands generate real time output and should be used with care. Only one option is the classic Cisco command for real time NAT debugging. Concept / Approach: Show commands such as show ip nat translations and show ip nat statistics display the current state of NAT tables and counters but do not print every translation event as it occurs. The debug ip nat command, on the other hand, instructs the router to log NAT events to the console, showing details for each packet that is being translated. This is the tool you use when you need to see how NAT behaves in real time for test packets or problematic flows. Step-by-Step Solution: Consider show ip nat translations: it displays the current table of inside local, inside global, outside local and outside global addresses but does not by itself show live changes packet by packet. Show ip nat statistics gives counters for hits, misses and details about pools, but it is still a snapshot, not a real time stream of events. The clear ip nat translations command resets the table and is used for maintenance but produces no steady real time feed of information. Debug ip nat is a debug command that prints a line of output each time a packet is translated or matched, making it ideal for watching real time NAT activity. Therefore, among the options, debug ip nat is the correct choice for real time translation monitoring. Verification / Alternative check: In a lab, enable debug ip nat and then generate some traffic from an inside host to an outside destination. You will see messages for each translation event, often showing inside local to inside global mappings and vice versa. When you disable the debug with undebug all or no debug ip nat, the stream of messages stops. This behaviour demonstrates that debug ip nat provides real time insight rather than static information. Why Other Options Are Wrong: Option a, show ip nat translations, is very useful but only shows a current list of mappings; it does not automatically update on screen in real time and is not a debug command. Common Pitfalls: Option b, show ip nat statistics, is often used to check whether a pool is in use and to see hit counts but again does not provide per packet logs. Option d, clear ip nat translations, can disrupt active sessions and should be used cautiously; it is not a monitoring tool. Option e, debug ip packet, produces very verbose output and may affect performance; it is not targeted specifically at NAT and is not the recommended way to watch translations. Common Pitfalls: Many administrators forget to turn off debug commands, which can flood the console and impact router performance, especially on busy devices. Always use debug ip nat carefully, preferably on lab gear or during controlled troubleshooting windows, and remember to disable it after you gather enough information. Combining debug ip nat with show ip nat translations can give you both real time insight and a summary view. Final Answer: The command that shows real time NAT translation activity is debug ip nat.

Question 2

You need to create a dynamic NAT pool named Todd that can provide exactly 30 usable global IPv4 addresses. Which ip nat pool command correctly defines the pool range and netmask on a Cisco router?

Accepted Answer

Introduction / Context: Dynamic NAT on Cisco routers uses pools of public or global IP addresses, allowing inside private addresses to be translated as needed. When defining a pool, you must choose a start and end address and an appropriate netmask. In this question, the goal is to create a pool named Todd that offers exactly 30 usable global addresses, so you must carefully evaluate the address range and netmask combination that delivers this number. Given Data / Assumptions: The pool is named Todd. Candidate pool ranges are given, for example 171.16.10.65 to 171.16.10.94. You want 30 usable addresses in the pool. The ip nat pool command requires a netmask parameter that matches the block of addresses. Concept / Approach: The range 171.16.10.65 through 171.16.10.94 contains 30 addresses because 94 minus 65 plus one equals 30. The underlying subnet for this range in a typical design would be 171.16.10.64 slash 27, whose subnet mask is 255.255.255.224. A slash 27 network has 32 addresses total, from 171.16.10.64 to 171.16.10.95, but you can choose to use only a subset of this block in your NAT pool. The netmask given in the pool command must reflect the actual subnet mask of the public network segment, not merely the count of addresses you wish to use. Step-by-Step Solution: Count the addresses in the candidate range 171.16.10.65 to 171.16.10.94. The difference is 29, and adding one gives 30 addresses, meeting the requirement. Identify the subnet to which this range belongs. The natural slash 27 network boundary around these addresses is 171.16.10.64 to 171.16.10.95, corresponding to subnet mask 255.255.255.224. Confirm that 255.255.255.224 is therefore the correct netmask for this public block. The correct ip nat pool command should therefore read ip nat pool Todd 171.16.10.65 171.16.10.94 netmask 255.255.255.224. Compare with options and see that option b matches exactly. Verification / Alternative check: You can verify the mask and range by converting 255.255.255.224 to binary to see that the increment in the last octet is 32, giving ranges that start at .0, .32, .64, .96 and so on. The block starting at 171.16.10.64 is valid, and 65 through 94 sit inside it. Using this subnet mask in the pool command tells the router how the global addresses are structured on the public side network. Why Other Options Are Wrong: Option a uses netmask 255.255.255.240, which is a slash 28 mask with a block size of 16 addresses. That does not match a range of 30 addresses and would be inconsistent with the actual subnet structure. Common Pitfalls: Option c uses the same range and netmask as option b but changes the pool name to lowercase todd, which is a different identifier. Names are case sensitive, so this does not match the requirement exactly. Option d defines a huge range from 171.16.10.1 to 171.16.10.254 with netmask 255.255.255.0, which provides far more than 30 addresses and may not be valid on the connected public network segment. Option e uses the full subnet range 171.16.10.64 to 171.16.10.95, which is 32 addresses, not the requested 30, so it does not answer the question precisely. Common Pitfalls: Students sometimes try to make the netmask match the number of addresses in the pool instead of the actual network design on the global side. Remember that NAT pools sit inside real subnets with fixed masks, and the chosen pool range must be compatible with that subnet. Correctly matching block sizes, network boundaries and address counts is an essential NAT design skill. Final Answer: The correct definition is ip nat pool Todd 171.16.10.65 171.16.10.94 netmask 255.255.255.224, which allocates 30 global addresses from a slash 27 subnet.

Question 3

When defining a pool of global addresses for Cisco NAT, which keyword can be used in place of the netmask parameter to specify the prefix length of the subnet?

Accepted Answer

Introduction / Context: When configuring a dynamic NAT pool on a Cisco router, you must specify both a range of global IP addresses and the subnet information for that range. Traditionally this is done with the netmask keyword followed by a dotted decimal subnet mask. Newer IOS versions also allow you to specify the subnet using prefix length notation, which can be more convenient and less error prone. Given Data / Assumptions: You are creating an ip nat pool statement on a Cisco router. You know that the command syntax supports netmask to define the subnet. You want to use an alternative form that uses a prefix length instead. One of the options corresponds to the actual Cisco IOS keyword for this feature. Concept / Approach: Cisco IOS supports two main ways to describe subnet information in NAT pool commands. The first is netmask, where you give a dotted decimal mask such as 255.255.255.224. The second is prefix-length, where you specify a numeric prefix such as 27. For example, ip nat pool Corp 198.18.41.129 198.18.41.134 prefix-length 29 is equivalent to using netmask 255.255.255.248. The actual keyword in the command is prefix-length, not a slash character by itself. Step-by-Step Solution: Recall the generic syntax for NAT pool configuration: ip nat pool name start-ip end-ip netmask mask or ip nat pool name start-ip end-ip prefix-length value. Identify the keyword in this syntax that replaces netmask; it is prefix-length followed by a number such as 24 or 27. Note that the slash symbol often used in CIDR notation, such as slash 24, is not used directly in the command as a standalone keyword. Compare the provided options with this knowledge and see that prefix-length is the correct IOS keyword. Therefore, option b is the correct answer. Verification / Alternative check: If you enter ip nat pool Test 10.1.1.1 10.1.1.6 ? at the CLI, IOS will display available keywords, including netmask and prefix-length. Choosing prefix-length 29 will configure the pool to use a slash 29 subnet. This kind of interactive help confirms the exact spelling of the keyword and demonstrates that it can be used in place of netmask. Why Other Options Are Wrong: Option a mentions slash notation, which is a way humans often write prefix lengths, such as 10.1.1.0 slash 24, but the literal slash character is not used as a keyword in the NAT pool command. Common Pitfalls: Option c, no mask, sounds like disabling a mask but does not exist as an IOS keyword in this context. Option d, block-size, might appeal to those thinking in terms of number of addresses, but Cisco NAT does not use this keyword in pool definitions. Option e, subnet-length, is not a Cisco command keyword and is likely included only as a distractor. Common Pitfalls: A frequent mistake is inconsistency between the pool range and the subnet definition. Whether you use netmask or prefix-length, ensure that the specified subnet correctly covers all addresses in the range and aligns with the actual network design. Using show ip nat statistics after configuration can help you verify that the pool is recognised correctly. Final Answer: Instead of netmask, you can use the prefix-length keyword to specify the subnet prefix length in a NAT pool definition.

Question 4

In Cisco NAT terminology, which address type represents the inside host address after translation, as it appears on the external or public network?

Accepted Answer

Introduction / Context: Cisco NAT terminology distinguishes several different views of addresses involved in translation. Understanding these terms is important for interpreting show commands and troubleshooting NAT behaviour. The inside and outside qualifiers describe whether an address belongs to the internal or external side of the network, while local and global describe whether the address is seen from the internal perspective or represents the address as seen in the global Internet. Given Data / Assumptions: An inside host has a private address that is translated by NAT. The question asks specifically about the inside host address after translation, that is, the address others on the external network will see. Cisco uses the four key labels inside local, inside global, outside local and outside global. Only one of these corresponds to the post translation address of the inside host. Concept / Approach: Inside local is the address assigned to an inside host before translation, often a private RFC 1918 address such as 192.168.1.10. Inside global is the address that the same inside host appears to have on the external network after translation, usually a public or routable address. Outside global is the real address of an outside host on the Internet, while outside local is how that outside host might be represented inside the local network in some NAT scenarios. For this question, we want the translated address of the inside host as seen externally, which is inside global. Step-by-Step Solution: Visualise a simple NAT example: an inside host 192.168.1.10 connects to the Internet through a router that maps it to 203.0.113.5. From the inside network perspective, 192.168.1.10 is the inside local address. This is the address configured on the host itself. The router translates this to 203.0.113.5 when sending packets out to the Internet. This public address is the inside global address, representing the inside host in the global address space. The outside web server might have an address such as 198.51.100.20. That address is the outside global address since it is the real address of the external host. Any special representation of that external address inside the local network would be referred to as an outside local address if such a mapping existed, which is not the case in this simple example. Verification / Alternative check: If you run show ip nat translations on a Cisco device, you will see a table with columns labelled inside local, inside global, outside local and outside global. Entries typically show something like 192.168.1.10 mapped to 203.0.113.5, confirming that 192.168.1.10 is inside local and 203.0.113.5 is inside global. This reinforces the definition that the inside host address after translation is the inside global. Why Other Options Are Wrong: Option a, inside local, is the inside host address before translation, usually private and not routable on the public Internet. Common Pitfalls: Option b, outside local, refers to how an external host might be represented inside the local network in advanced NAT scenarios; it does not describe the inside host after translation. Option d, outside global, is the genuine address of an outside host in the global Internet, not of the inside host. Option e, public outside, is not standard Cisco terminology and should not be used when discussing NAT types in exam contexts. Common Pitfalls: Students often confuse local and global, assuming that local always means private and global always means public. In reality, these terms describe perspective: local is how the address appears from inside the network, and global is how it appears from outside. Similarly, inside and outside refer to which side of the NAT boundary the host lives on. Keeping these two axes clear will make NAT troubleshooting much easier. Final Answer: The inside host address after translation, as seen on the external network, is called the inside global address.

Question 5

Your inside local addresses are not being translated to inside global addresses using a NAT pool on a Cisco router. Given the configuration ip nat pool Corp 198.18.41.129 198.18.41.134 netmask 255.255.255.248 and ip nat inside source list 100 pool C…

Accepted Answer

Introduction / Context: When NAT does not appear to be working, you need to quickly determine whether the NAT pool is configured correctly and whether inside hosts are actually using that pool. Cisco provides several show commands for NAT, each focusing on different aspects such as individual translations, overall statistics or pool utilisation. Choosing the right command can make troubleshooting much faster and more effective. Given Data / Assumptions: The NAT pool Corp is defined from 198.18.41.129 to 198.18.41.134 with a slash 29 netmask 255.255.255.248. Dynamic NAT with overload is configured using ip nat inside source list 100 pool Corp overload. Inside local addresses are not being translated to inside global addresses as expected. You want to verify whether the pool is active, how many addresses are allocated and whether overload is in effect. Concept / Approach: Show ip nat translations lists current translation entries, but if no translations are happening yet, it may be empty and not directly explain why. Show ip nat statistics provides a summary that includes information about the configured pools, how many addresses are in each, how many have been allocated and whether overload is enabled. This command is ideal for confirming that inside globals are permitted to use the defined NAT pool and for checking overall NAT status. Step-by-Step Solution: Recognise that you need an overview that connects the NAT pool to its usage, not just individual translation entries. The debug ip nat command can show real time activity but can be noisy and may not show anything if traffic is not yet flowing; it is better used after initial sanity checks. Show access-list can confirm whether ACL 100 is matching packets, but it does not directly tell you whether the pool Corp is being utilised. Show ip nat translation shows existing translations but not whether the pool is healthy if there are no active flows. Show ip nat statistics displays pool Corp, the address range, the total and used addresses and information about overload, making it the best command to verify whether inside globals are configured to use the pool. Verification / Alternative check: When you run show ip nat statistics on a router with the given configuration, the output will list something like pool Corp, 198.18.41.129 198.18.41.134, netmask 255.255.255.248, and may show figures for addresses in use and out of use. It will also show the number of dynamic translations and whether there is an overload configuration. This summary confirms that the pool exists, that its size is correct and that the router will use it for translations matching ACL 100. Why Other Options Are Wrong: Option a, debug ip nat, is useful after you have verified basic configuration, but on its own it does not summarise pool definitions and can generate a lot of output that may be hard to interpret at first glance. Common Pitfalls: Option b, show access-list, can be very helpful to verify whether ACL 100 is matching traffic, but it does not display anything about the NAT pool or overload configuration. Option c, show ip nat translation, is excellent for seeing specific inside local to inside global mappings but might be empty and therefore not informative until traffic flows correctly. Option e, show running-config nat, is not a standard command; you would instead use show running-config and manually inspect the NAT section, which is slower than using purpose built show commands. Common Pitfalls: A common mistake is to jump straight into debug commands without first confirming that the basic NAT definitions and ACLs are correct. Show ip nat statistics offers a safe, low impact way to verify configuration and usage before resorting to more intrusive debugging. Combining this with show access-list and show ip nat translations forms a powerful troubleshooting trio. Final Answer: To verify that inside globals are allowed to use the NAT pool and to see pool usage, you should use show ip nat statistics.

Question 6

In Cisco terminology, Port Address Translation is commonly referred to by which other NAT feature name that describes many inside addresses sharing a single public IP?

Accepted Answer

Introduction / Context: Port Address Translation, or PAT, is a very common form of NAT that allows many internal devices to share a small number of public IP addresses, often just one. Cisco documentation and exam questions often use a specific term for this feature that emphasises how multiple inside addresses are mapped to a single global address by overloading it with different port numbers. Recognising this synonym is important for correctly interpreting configuration guides and exam scenarios. Given Data / Assumptions: PAT maps multiple inside local addresses to one or a few inside global addresses by using different source port numbers. Cisco IOS implements this behaviour with the overload keyword in NAT configuration. The question asks specifically what PAT Address Translation is also called in Cisco terminology. Only one option matches the widely used term in Cisco training material. Concept / Approach: When you configure ip nat inside source list 1 interface serial0 overload or ip nat inside source list 1 pool Corp overload, the overload keyword enables many to one translation using port numbers. This is exactly how PAT works. Because of this overload keyword, Cisco often refers to PAT as NAT Overload. In many training texts, the phrases PAT and NAT Overload are used almost interchangeably. Step-by-Step Solution: Recall that static NAT creates a one to one mapping and is not called PAT. Dynamic NAT with a pool creates many to many mappings without reusing addresses by ports; this is still not PAT. PAT specifically allows many internal addresses to share one global address by using port numbers, and is configured with the overload keyword. The presence of overload in configuration syntax leads to the descriptive name NAT Overload for this type of translation. Among the options, NAT Overload is the only one that matches this widely recognised name. Verification / Alternative check: Looking at Cisco examples, you will often see explanatory comments such as ip nat inside source list 1 interface serial0 overload, which is called NAT Overload or PAT. Books and official training material repeatedly state that NAT overload is the Cisco term for PAT. This confirms that NAT Overload is the correct synonym. Why Other Options Are Wrong: Option a, NAT Fast, is not a standard term for any NAT feature and appears only as a distractor. Common Pitfalls: Option b, NAT Static, refers to static one to one mappings, which do not multiplex many hosts behind a single address and do not use port overloading. Option d, Overloading Static, combines words in a way that does not match any official Cisco feature name. Option e, Port Forwarding, is related to static NAT or translation of specific ports for inbound traffic, but it is not the same concept as PAT for outbound sessions. Common Pitfalls: A frequent misunderstanding is to treat all NAT features as the same and ignore the differences between static NAT, dynamic NAT and PAT. In practice, PAT or NAT Overload is the most widely deployed form for home and small office Internet access, because it conserves public addresses. Remember that any NAT configuration using the overload keyword is implementing PAT or NAT Overload. Final Answer: PAT Address Translation is also called NAT Overload in Cisco terminology.

Question 7

Which type of Cisco address translation allows thousands of internal hosts to share a single public IP address by using different TCP and UDP port numbers for each session?

Accepted Answer

Introduction / Context: Public IPv4 addresses are scarce, so most organisations and almost all home networks cannot assign a unique public IP to every internal device. Instead they rely on a form of NAT that lets many internal hosts share a single public address by multiplexing connections through different port numbers. This approach is called Port Address Translation, or PAT, and is implemented with the overload keyword in Cisco configurations. Given Data / Assumptions: There is only one or a very small number of public IP addresses available. You need to allow potentially thousands of internal hosts to access the Internet. The translation method must distinguish sessions by port numbers, not only by IP addresses. Cisco IOS offers static NAT, dynamic NAT and PAT or NAT Overload as options. Concept / Approach: Static NAT creates a permanent one to one mapping between an inside local and an inside global address, which cannot scale to thousands of hosts sharing one address. Dynamic NAT uses a pool of inside global addresses and maps inside locals to them as needed, but each mapping still consumes one public address. PAT or NAT Overload, by contrast, maps multiple inside local addresses to a single inside global address by assigning unique source port numbers for each active session. This allows thousands of simultaneous translations using only one or a few public IPs. Step-by-Step Solution: Recognise the requirement: thousands of hosts must share one address, which rules out pure static NAT and simple dynamic NAT without port reuse. Recall that PAT is configured with commands like ip nat inside source list 1 interface serial0 overload, where overload is the key to sharing a single address among many hosts. Under PAT, the router keeps track of each internal host and session by using a combination of the inside global address and a unique source port, allowing many internal addresses to appear to come from the same public IP. This behaviour matches the description given in the question exactly. Therefore, Port Address Translation using NAT Overload is the correct translation type. Verification / Alternative check: You can verify PAT behaviour with show ip nat translations, which will show multiple entries sharing the same inside global address but using different port numbers, such as tcp 203.0.113.5:30001 mapping to 192.168.1.10:1025 and tcp 203.0.113.5:30002 mapping to 192.168.1.11:1025. This demonstrates how a single public IP can represent many internal hosts simultaneously, which is characteristic of PAT. Why Other Options Are Wrong: Option a, static one to one NAT, assigns a dedicated global address for each internal host and cannot scale to thousands of hosts with only one public IP. Common Pitfalls: Option b, dynamic many to many NAT using a pool, still requires a public address for each concurrent internal host and therefore does not allow thousands of hosts to share a single address. Option d, policy based NAT, refers to NAT decisions that depend on policies such as source or destination, but it does not inherently address the many to one scaling described here. Option e, outside source static NAT, maps external addresses into the inside network for special use cases and does not match the scenario of internal hosts going out through one public IP. Common Pitfalls: A common misunderstanding is equating any NAT configuration with PAT. Only configurations that use overload or explicit port mapping behave as PAT, allowing large numbers of hosts to share a small number of addresses. Knowing which NAT type you are using is crucial when diagnosing issues with simultaneous connections, port exhaustion or address shortages. Final Answer: The translation type that allows thousands of hosts to share a single address is Port Address Translation (PAT) using NAT Overload.

Question 8

Given the Cisco NAT configuration snippet ip nat pool todd-nat 170.168.10.10 170.168.10.20 netmask 255.255.255.0, what general type of NAT is being configured when this pool is used in an ip nat inside source command without the overload keyword?

Accepted Answer

Introduction / Context: Cisco NAT supports several distinct modes: static NAT, dynamic NAT and Port Address Translation. The presence of a nat pool statement suggests that dynamic mappings may be created from that pool, but the exact type of NAT in use depends on how the pool is referenced in ip nat inside source commands. Recognising NAT types based on configuration fragments is a common exam and troubleshooting skill. Given Data / Assumptions: The configuration includes ip nat pool todd-nat 170.168.10.10 170.168.10.20 netmask 255.255.255.0. This defines a range of inside global addresses from 170.168.10.10 to 170.168.10.20. We assume that an ip nat inside source list statement refers to this pool without the overload keyword. The question asks for the type of NAT implied by using such a pool. Concept / Approach: Static NAT is configured with ip nat inside source static commands and does not use pools. PAT, or NAT Overload, adds the overload keyword to ip nat inside source list or route map commands to allow many inside locals to share a single inside global address via ports. Dynamic NAT uses ip nat inside source list list-number pool pool-name without overload, mapping each inside local to an available address from the pool on a first come first served basis. Therefore, the presence of a nat pool and its use without overload points to dynamic NAT. Step-by-Step Solution: Observe that ip nat pool todd-nat defines a named pool of inside global addresses. Pools are typically used for dynamic NAT or PAT, not for static one to one mappings. Static NAT configurations instead list each mapping individually with ip nat inside source static inside-address outside-address and do not reference pools like todd-nat. PAT requires the overload keyword, as in ip nat inside source list 1 pool todd-nat overload, to reuse a single address for many translations using ports. In this scenario, the question specifically mentions that the pool is used without overload, implying that each translation consumes a dedicated global address from the pool. That behaviour matches the definition of dynamic NAT using a pool of global addresses, where each inside local is dynamically mapped to one of the pool addresses, and the mapping is removed when sessions end. Verification / Alternative check: If you configure ip nat inside source list 1 pool todd-nat and then generate traffic from several inside hosts, show ip nat translations will show a series of one to one mappings, each using a different address from 170.168.10.10 through 170.168.10.20. Once the pool is exhausted, additional hosts cannot be translated. This is classic dynamic NAT behaviour and is distinct from PAT, where many hosts can share a single global address. Why Other Options Are Wrong: Option a, static one to one NAT, does not use address pools and instead creates fixed individual mappings with static statements. Common Pitfalls: Option c, PAT with overload, would require the overload keyword, which is absent in the description and would typically use one or a small number of global addresses rather than a larger range. Option d, NAT exemption, refers to configurations that bypass NAT for some traffic and does not involve pools in this way. Option e, outside source static NAT, involves mapping external addresses into the inside network and uses different configuration forms, not the simple inside source pool usage described here. Common Pitfalls: Students sometimes assume that any configuration involving a pool must be PAT, but this is not the case. The overload keyword is the key indicator of PAT, whereas a pool without overload indicates dynamic NAT. Always look for both the nat pool statement and how it is referenced in ip nat inside source commands to correctly identify the NAT type. Final Answer: The configuration is setting up dynamic NAT using a pool of global addresses when the pool is referenced without overload.

Question 9

In IEEE 802.11 wireless networking, what is the operating frequency band used by the 802.11g standard?

Accepted Answer

Introduction / Context: The IEEE 802.11 family of standards defines wireless LAN technologies that operate in different frequency bands and support various data rates. Knowing which standard uses which band is fundamental for wireless design, interference analysis and exam preparation. The 802.11g standard is a widely deployed legacy standard that extended earlier 2.4 GHz technologies while increasing throughput. Given Data / Assumptions: We are dealing with the IEEE 802.11g wireless LAN standard. The question asks specifically about its frequency band, not its data rate. 802.11g was designed as an evolution of 802.11b. Other 802.11 variants such as 802.11a and 802.11ac use different frequency bands. Concept / Approach: IEEE 802.11g operates in the 2.4 GHz ISM band, the same frequency range used by 802.11b. It was designed to provide higher data rates while maintaining backward compatibility with 802.11b devices. In contrast, 802.11a operates in the 5 GHz band, and more modern standards such as 802.11n and 802.11ac can operate in both bands or extend into higher frequency ranges. Therefore, the correct answer must indicate the 2.4 GHz band. Step-by-Step Solution: Recall that 802.11g was introduced as a higher speed extension of 802.11b, which already used the 2.4 GHz band, so 802.11g also uses 2.4 GHz. Remember that 802.11a was the standard that primarily used the 5 GHz band instead, so 5 GHz is not correct for 802.11g. Data rates are measured in Mbps, not Gbps, for 802.11g, so any option that lists Gbps is confusing frequency with throughput and should be considered incorrect in this context. The option that correctly names the operating band is 2.4 GHz. Therefore, option c is the correct answer. Verification / Alternative check: Vendor datasheets and Wi-Fi certification documents typically list 802.11b and 802.11g as operating in the 2.4 GHz band, usually in the 2.4 to 2.4835 GHz range, depending on regulatory domains. Conversely, they list 802.11a and some later 802.11ac and 802.11ax modes as operating in the 5 GHz band. This reinforces that 802.11g is firmly associated with 2.4 GHz. Why Other Options Are Wrong: Option a, 2.4 Gbps, confuses a frequency label with a data rate in gigabits per second and does not accurately describe a wireless band. Common Pitfalls: Option b, 5 Gbps, again uses the wrong unit and band, and more closely relates to later multistream technologies, not 802.11g. Option d, 5 GHz, is correct for 802.11a and parts of 802.11n and 802.11ac, but not for 802.11g. Option e, 900 MHz, is used in some specialised wireless systems but is not part of mainstream IEEE 802.11 WLAN standards like 802.11g. Common Pitfalls: A common source of confusion is mixing up which standards use 2.4 GHz and which use 5 GHz, especially now that dual band access points are common. A simple memory aid is that 802.11b and 802.11g are 2.4 GHz, while the original 802.11a is 5 GHz. Later standards like 802.11n can use both bands, and 802.11ac and newer primarily use 5 GHz and beyond. Final Answer: The IEEE 802.11g standard operates in the 2.4 GHz frequency band.

Question 10

After physically installing a wireless access point on the ceiling of your office, which configuration parameter must be set at a minimum so that wireless clients can associate and operate on that access point?

Accepted Answer

Introduction / Context: Wireless access points provide connectivity to clients over the air, but before clients can associate with an access point, at least some basic configuration must be present. Modern deployments normally use security features such as WPA2 with AES and pre shared keys or enterprise authentication, but the absolute minimum requirement for any client to join a network is that there is a network name to identify the wireless service set. Given Data / Assumptions: The access point hardware has been installed and powered on. You are asked for the minimum configuration needed to let a wireless client operate on it. Security is desirable but not strictly required in the question. Wireless clients need to know which network to join by name. Concept / Approach: Wireless networks are identified by a Service Set Identifier, or SSID. This is the name that clients see when they scan for available networks. An access point can broadcast one or more SSIDs. If an access point has no SSID configured, clients cannot associate because there is no defined network to join. Security parameters such as AES, PSK, WEP or RADIUS servers are important in practice but are not absolutely required for a basic open network; an open SSID without encryption can still operate in many configurations, although it is not secure. Step-by-Step Solution: Consider the absolute basics: a client must know which wireless network to join, and that network is identified by its SSID. Without an SSID, the access point has no defined logical wireless network for clients to see or attach to. AES, PSK and WEP are all related to encryption and authentication. They are important for security but an access point could theoretically run an open SSID with no encryption at all, in which case those settings would not be needed. A RADIUS server is required only for enterprise authentication methods such as WPA2 Enterprise, not for basic open or personal networks. Therefore, the one parameter that absolutely must be set is the SSID. Verification / Alternative check: In configuration interfaces for most wireless access points, the initial setup wizard asks you to choose an SSID, often with a default name provided by the vendor. Even if you skip security settings, the access point will start broadcasting that SSID and clients will be able to connect to it in open mode. This behaviour confirms that SSID is the minimum required configuration item for basic operation. Why Other Options Are Wrong: Option a, AES encryption key, is part of WPA2 security but is not strictly required to bring up a basic open network. Common Pitfalls: Option b, PSK, is a pre shared key used with WPA or WPA2 Personal. An open network does not use a PSK, so this is optional from a pure connectivity perspective. Option d, WEP static key, refers to an older and insecure encryption method that should not be used; again, encryption is not mandatory for basic association in this question. Option e, a RADIUS server address, is used only for enterprise authentication methods and is not required in simple deployments. Common Pitfalls: Students sometimes assume that security configuration is always mandatory, but many lab and small test setups use open SSIDs for simplicity. While security should always be considered in real environments, exam questions that ask for the minimum required parameter are usually looking for SSID as the answer. Always read carefully whether the question is about basic functionality or secure best practice. Final Answer: At a minimum, you must configure an SSID (wireless network name) on the access point so that clients can see and join the network.

Question 11

For Wi-Fi networks using WPA2 security, which encryption and integrity suite is defined as the standard method for protecting wireless frames?

Accepted Answer

Introduction / Context: Wi-Fi Protected Access, or WPA, was introduced to improve the security of wireless LANs beyond what WEP could provide. WPA2 is the second generation of this standard and is widely recommended as the minimum security level for modern deployments. A key part of WPA2 is the encryption and integrity suite used to protect data frames on the air. Understanding which cipher and mode belong to WPA2 is a common exam topic. Given Data / Assumptions: We are specifically discussing WPA2, not WPA or WEP. The question asks about the encryption type used by WPA2, not about the authentication method such as PSK or 802.1X. Several cipher suites appear in historical wireless security, including TKIP and AES. Only one suite is defined in the core WPA2 standard as the primary data protection mechanism. Concept / Approach: WPA originally introduced TKIP with MIC as an improvement over WEP, but it still had limitations. WPA2 moved to a stronger and more modern cipher: the Advanced Encryption Standard in Counter Mode with Cipher Block Chaining Message Authentication Code Protocol, abbreviated AES CCMP. This combination provides both confidentiality and integrity. PSK refers to a key distribution method, not an encryption algorithm, and WEP based methods are obsolete and insecure. Step-by-Step Solution: Recall that WPA2 is based on the IEEE 802.11i amendment, which specifies AES CCMP as the required encryption and integrity mechanism. Recognise that TKIP with MIC was introduced with WPA, sometimes referred to as WPA version 1, but it is not the primary suite for WPA2 and is discouraged in modern deployments. Understand that PSK simply means pre shared key and describes how keys are managed, not how encryption itself is performed. WEP and related phrases such as PPK via IV refer to older RC4 based methods using initialization vectors, which are vulnerable and not part of WPA2 best practice. The only option that correctly names the WPA2 encryption suite is AES-CCMP. Verification / Alternative check: Reading Wi-Fi Alliance certification details and IEEE 802.11i documentation confirms that WPA2 Certified devices must support AES CCMP for robust security. Many enterprise Wi-Fi designs explicitly require WPA2 with AES, distinguishing it from older WPA with TKIP. Although some mixed mode configurations allow legacy clients, the standard expectation for WPA2 security is AES CCMP. Why Other Options Are Wrong: Option b, PPK via IV, is not a standard name for any WPA2 cipher suite and loosely resembles WEP concepts rather than modern AES based security. Common Pitfalls: Option c, PSK, is often misinterpreted as an encryption algorithm, but it only describes the use of a pre shared key for authentication in WPA or WPA2 Personal modes. Encryption is still provided by TKIP or AES underneath. Option d, TKIP/MIC, corresponds to the cipher suite introduced with WPA version 1, not WPA2, and is considered legacy and less secure. Option e, WEP with shared key, is the original and now deprecated wireless security method that WPA and WPA2 were designed to replace. Common Pitfalls: Learners sometimes mix up security mode labels in consumer Wi-Fi routers, which might display options such as WPA2 Personal (AES) or WPA/WPA2 Mixed (TKIP/AES). For exams, remember that pure WPA2 security refers to AES CCMP, and TKIP is associated with WPA. Always distinguish between key management methods like PSK and actual encryption suites like AES CCMP. Final Answer: WPA2 uses the AES-CCMP encryption and integrity suite to protect wireless frames.

Question 12

What is the maximum theoretical data rate defined by the IEEE 802.11g wireless LAN standard?

Accepted Answer

Introduction / Context: Each IEEE 802.11 wireless standard specifies a set of possible data rates that can be used on the air. The maximum theoretical data rate is often quoted when comparing standards such as 802.11b, 802.11g and 802.11n. While real world throughput is usually lower due to overhead and signal conditions, the standardised maximum provides a convenient way to distinguish technologies in exam questions. Given Data / Assumptions: We are concerned with the 802.11g standard. The question asks for the maximum theoretical physical layer data rate, not real world throughput. Common reference speeds include 11 Mbps for 802.11b and 54 Mbps for 802.11a and 802.11g. Some proprietary modes may advertise higher speeds, but the question focuses on the standard itself. Concept / Approach: IEEE 802.11b supports up to 11 Mbps using DSSS modulation in the 2.4 GHz band. IEEE 802.11a supports up to 54 Mbps using OFDM modulation in the 5 GHz band. IEEE 802.11g brought OFDM to the 2.4 GHz band and also supports a maximum data rate of 54 Mbps under ideal conditions. Some vendors later introduced non standard channel bonding or turbo modes with higher numbers, but those fall outside the core IEEE 802.11g specification. Step-by-Step Solution: Recall that the main improvement of 802.11g over 802.11b is the jump from 11 Mbps to 54 Mbps in the same 2.4 GHz band. Check the options: 6 Mbps, 11 Mbps and 22 Mbps are lower data rates associated with various modulation schemes in 802.11a, 802.11b and some proprietary extensions. 54 Mbps appears both in 802.11a and 802.11g as the top standard data rate. Some vendors offered 108 Mbps modes by bonding channels or using proprietary features, but these are not part of the base IEEE 802.11g standard and typically require matching hardware. Therefore, the correct maximum data rate defined by 802.11g is 54 Mbps. Verification / Alternative check: Wireless textbooks and Wi-Fi Alliance materials list 802.11g as offering data rates from 1 Mbps up to 54 Mbps. The actual throughput available to applications is usually around half of that or less due to protocol overhead, shared medium contention and environmental factors. Despite this, 54 Mbps remains the official maximum physical rate, which is what exam questions refer to. Why Other Options Are Wrong: Option a, 6 Mbps, is one of the lower data rates supported by 802.11a and 802.11g but is not the maximum. Common Pitfalls: Option b, 11 Mbps, is the maximum for 802.11b, not 802.11g. Option c, 22 Mbps, sometimes appears in proprietary enhancements to 802.11b or mixed environments but is not the official 802.11g top speed. Option e, 108 Mbps with channel bonding, refers to vendor specific enhancements rather than the core IEEE 802.11g standard and should not be chosen in a standards based exam question. Common Pitfalls: Many learners confuse real throughput with theoretical data rate or assume that all 802.11 standards have similar maxima. Remember the simple mapping: 802.11b up to 11 Mbps, 802.11a and 802.11g up to 54 Mbps, and 802.11n and newer potentially much higher depending on channel width and spatial streams. Final Answer: The maximum data rate for IEEE 802.11g is 54 Mbps.

Question 13

A wireless client with an 802.11b/g network card cannot connect to an 802.11b/g basic service set, and the access point client list shows no active wireless LAN clients. Which configuration problem on the client is the most likely cause of this fail…

Accepted Answer

Introduction / Context: In enterprise and small office wireless LANs, a very common support issue is a user reporting that a wireless client cannot connect to an access point or basic service set. Understanding which configuration parameters must match between the client and the access point is critical for quickly diagnosing why a client does not even appear in the access point association or client list. Given Data / Assumptions: The wireless network uses 802.11b/g in a basic service set (BSS) with a single access point. The client has an 802.11b/g compatible wireless card. The access point client section shows no associated or active wireless LAN clients. The question asks for the most likely configuration error on the client that prevents association. Concept / Approach: The client must first discover the wireless network and then associate at Layer 2 before any IP configuration is relevant. Discovery and association rely on the service set identifier (SSID), security settings, and radio parameters. In most environments, the client scans the available channels automatically, so mismatched manual channel configuration is less common. An incorrect IP address or default gateway will not prevent association and therefore will still allow the access point to list the client as associated. In contrast, if the SSID on the client does not match the SSID that the access point is advertising, the client will not join that BSS at all, and the access point will show no associated client. Step-by-Step Solution: 1. For a client to appear in the access point client list, it must complete the 802.11 association process at Layer 2.2. The client must send probe or association requests that include the SSID of the network it wants to join.3. The access point must be advertising the same SSID for the client to recognize and select that BSS.4. If the SSID configured on the client does not match the access point SSID, the client will never successfully associate with that access point.5. Because association never completes, the access point client table shows no active wireless LAN clients. Verification / Alternative check: An administrator can verify this by checking the client wireless profile and comparing the SSID string with the SSID configured on the access point. Correcting the SSID value or selecting the proper network from the list of available wireless networks typically immediately allows the client to associate and appear in the access point client list, confirming that the mismatch was the root cause. Why Other Options Are Wrong: Option A, an incorrect RF channel, is less likely because most modern clients automatically scan all 2.4 GHz channels to discover access points and do not require a manually configured channel. Option B, an IP address in the wrong subnet, does not prevent Layer 2 association and would still allow the client to appear in the access point table, although Layer 3 connectivity would fail. Option C, an incorrect pre-shared key, can prevent successful authentication, but in many implementations the client may still temporarily appear as an associating station before the key exchange fails, and the question highlights a configuration that cleanly prevents association. Option E, a wrong default gateway, affects routing beyond the local subnet but does not stop the 802.11 association process. Common Pitfalls: A frequent mistake is to troubleshoot IP addressing first when the problem is really that the client never joins the wireless LAN at all. Another pitfall is to overlook simple SSID spelling differences, including upper and lower case, hidden SSID settings, or accidental connection to a neighbor network with a similar name. Checking that the SSID configured on the client exactly matches the intended wireless network should be one of the first steps in any wireless troubleshooting process. Final Answer: The wireless client has the service set identifier (SSID) configured incorrectly.

Question 14

Two employees have created a direct wireless connection between their laptops with no access point present. Which type of 802.11 wireless topology have they formed?

Accepted Answer

Introduction / Context: Wireless LANs based on IEEE 802.11 can be deployed in several topologies, including basic service sets, extended service sets, and independent basic service sets. Many certification exams test your ability to recognize when a particular scenario describes a centralized access point based design versus a direct peer to peer ad hoc network between wireless clients. Given Data / Assumptions: Two workers are using wireless laptops. They have established communication directly between the laptops. No access point or wireless controller is mentioned in the scenario. The question asks which topology has been created by this direct connection. Concept / Approach: A basic service set (BSS) uses an access point as the central device that all wireless clients associate with. An extended service set (ESS) consists of multiple BSSs connected through a distribution system such as a wired Ethernet backbone. An independent basic service set (IBSS) is different: it is an ad hoc network in which wireless clients communicate directly with one another without any access point. The key phrase in the scenario is that the workers connected their laptops directly, which immediately suggests an IBSS. Step-by-Step Solution: 1. Identify whether an access point is present in the scenario. The text explicitly states that the laptops connect directly, and no access point is named.2. Recall that a BSS always includes a single access point that forms the center of that wireless cell.3. Recall that an ESS is built from multiple BSSs and therefore still depends on one or more access points connected by a distribution system.4. Recognize that an IBSS is defined as an independent basic service set, commonly referred to as ad hoc mode, in which stations communicate peer to peer without infrastructure.5. Because the laptops are communicating directly with each other and no infrastructure device is present, this scenario exactly matches an IBSS. Verification / Alternative check: If you configure two laptops in ad hoc mode in a lab, you will see that they form a temporary network without requiring an access point. Tools such as wireless configuration utilities will label this as ad hoc or peer to peer. In contrast, when connecting to a typical office Wi-Fi, you always see an access point or wireless router as the device you associate with, which is characteristic of a BSS or ESS, not an IBSS. Why Other Options Are Wrong: Option A, BSS, is incorrect because a BSS requires an access point. Option B, SSID, is not a topology at all; it is simply the name string used to identify a wireless network. Option D, ESS, describes multiple BSSs tied together by a distribution system, again requiring one or more access points, which are absent in this scenario. Common Pitfalls: Candidates sometimes confuse the term IBSS with BSS and forget that the presence or absence of an access point is the key difference. Another common issue is thinking that any two clients on the same Wi-Fi network are in ad hoc mode, when in fact they may both be associated to the same access point in a BSS or ESS. Always look for phrases like direct connection with no access point to identify an IBSS. Final Answer: Independent Basic Service Set (IBSS, ad hoc mode)

Question 15

While configuring an access point in root mode, you see the term extended service set identifier (ESSID). What does an extended service set represent in an 802.11 wireless LAN?

Accepted Answer

Introduction / Context: 802.11 wireless LANs scale beyond a single access point by creating extended service sets. For network designers and certification candidates, it is important to understand how basic service sets, distribution systems, and extended service sets work together to provide seamless coverage across larger areas such as entire floors or buildings. Given Data / Assumptions: An access point is being configured in root mode, which normally connects to a wired distribution system. The configuration references an extended service set identifier (ESSID). Several access points are expected to provide coverage in the same logical wireless network. The question asks what the extended service set represents. Concept / Approach: A basic service set (BSS) is a single access point plus the stations associated with it. When multiple BSSs use the same SSID and are connected by a common distribution system, such as an Ethernet backbone and switches, they form an extended service set (ESS). Clients can roam between these BSSs while maintaining connectivity to the same logical network. The extended service set identifier is essentially the SSID used to identify this group of BSSs as one extended network. Step-by-Step Solution: 1. Identify that the access point is a root device, which means it connects to the wired distribution system rather than acting purely as a repeater.2. Recall that each access point and its associated clients form a basic service set.3. When multiple access points advertise the same SSID and share the same distribution system, clients can associate with whichever signal is strongest and still be on the same logical network.4. The collection of these basic service sets forms an extended service set.5. Therefore, the extended service set represents multiple access points sharing one SSID and connected through a distribution system. Verification / Alternative check: If you walk through an office building and your wireless client continues to show the same network name while your signal transitions between different access points, you are experiencing an extended service set. Network diagrams and controller configurations typically show several access points grouped under one WLAN profile, which is another way of expressing an ESS. Why Other Options Are Wrong: Option B suggests separate SSIDs on each access point, which would create multiple distinct wireless networks rather than one extended service set. Option C focuses on buildings and broadcast domains, but physical placement alone does not define an ESS; it is the shared SSID and common distribution system that matter. Option D mentions a repeater access point, which is a deployment detail and does not define the concept of an extended service set. Common Pitfalls: Students often confuse SSID, BSS, and ESS. Remember that a single SSID can be broadcast by many access points, and when those access points are tied together by a common distribution system, they collectively form an ESS. Misunderstanding this can lead to incorrect roaming designs or misinterpretation of wireless survey results. Final Answer: More than one access point using the same SSID and connected through a distribution system, forming a single logical wireless LAN.

Question 16

In Internet Protocol version 6 (IPv6), how many bits are present in a full IPv6 address field?

Accepted Answer

Introduction / Context: IPv6 was introduced to overcome the address exhaustion and limitations of IPv4. One of the most fundamental facts about IPv6 that every networking professional must know is the length of an IPv6 address in bits. This directly affects how many unique addresses are available and how IPv6 subnets are designed. Given Data / Assumptions: We are working with native IPv6 addressing, not IPv4-mapped or tunneled addresses. IPv4 addresses are commonly known to be 32 bits long. The question asks specifically for the number of bits in a standard IPv6 address. No unusual address compression or special forms change the underlying bit length. Concept / Approach: An IPv6 address is defined as a 128 bit value. It is usually written as eight groups of four hexadecimal digits separated by colons. Each hexadecimal digit represents four bits, so each group of four hexadecimal digits equals 16 bits. Eight such groups give 8 * 16 = 128 bits total. Even when shorthand notation like zero compression is used, the actual address remains 128 bits internally. Step-by-Step Solution: 1. Observe the standard textual representation of IPv6, for example 2001:0db8:0000:0000:0000:ff00:0042:8329.2. Count the number of groups: there are eight groups separated by colons.3. Each group contains four hexadecimal digits. Each hexadecimal digit represents four bits.4. Therefore, each group represents 4 * 4 = 16 bits of the address.5. Multiply 16 bits per group by eight groups to get 16 * 8 = 128 bits for the full IPv6 address. Verification / Alternative check: Standards documents such as the IPv6 base specification and networking references all state that IPv6 uses 128 bit addresses. You can also verify by converting an IPv6 address to binary and counting the bits: an uncompressed address yields 32 hexadecimal digits, and 32 * 4 equals 128 binary digits. Why Other Options Are Wrong: Option A, 24 bits, and option B, 16 bits, are far too small for Internet addressing and are not associated with IP address lengths. Option C, 32 bits, corresponds to an IPv4 address, not an IPv6 address. IPv6 intentionally expanded the address space from 32 to 128 bits to provide an enormous number of unique addresses. Common Pitfalls: Some learners mistakenly assume that because IPv4 uses 32 bit addresses, IPv6 might use a modestly larger size such as 64 bits. In reality, 64 bits would still be too small for long term global addressing needs, so IPv6 uses 128 bits. Another source of confusion is the presence of interface identifiers and subnet prefixes, but together these still make up the same 128 bit address. Final Answer: 128 bits

Question 17

Which of the following statements correctly describes a key characteristic of Internet Protocol version 6 (IPv6)?

Accepted Answer

Introduction / Context: IPv6 introduces several important improvements over IPv4, including a vastly larger address space, simplified header structure, and changes in how traffic is sent to multiple destinations. Exams often test whether you can distinguish accurate statements about IPv6 design goals from common misconceptions. Given Data / Assumptions: We are comparing basic IPv6 features with those of IPv4. Broadcast traffic in IPv4 can be inefficient and noisy on large networks. IPv6 was designed to improve efficiency and scalability in large networks. The question asks which description of IPv6 is correct. Concept / Approach: One of the key design decisions in IPv6 was to eliminate the concept of a broadcast address. Instead of sending packets to all nodes in a subnet with a broadcast, IPv6 uses multicast addresses targeted at specific groups and anycast addresses to reach one representative of a group. This reduces unnecessary traffic and improves control over who receives particular messages. IPv6 also keeps hierarchical addressing to support efficient routing, and interfaces can and often do use multiple IPv6 addresses simultaneously. Step-by-Step Solution: 1. Evaluate option B first because it mentions broadcasts, multicast, and anycast.2. Confirm that IPv6 indeed removes broadcast addresses and uses multicast groups such as all nodes and all routers for control traffic.3. Note that anycast addresses in IPv6 allow a packet to be delivered to the nearest member of a set of nodes that share the same anycast address.4. Recognize that this description matches documented IPv6 behavior and goals.5. Compare the other options and identify that they contradict standard IPv6 features. Verification / Alternative check: IPv6 standards and textbooks explicitly mention that there is no broadcast address in IPv6. Instead, special multicast addresses such as FF02::1 (all nodes) and FF02::2 (all routers) are used. Routing and Neighbor Discovery protocols rely on these multicast addresses rather than broadcast flooding. Why Other Options Are Wrong: Option A is incorrect because IPv6 addresses are allocated hierarchically by registries and providers to support aggregation in routing tables. Option C is wrong because IPv6 defines an address space of 2^128 addresses, which is far more than 2.7 billion. Option D is incorrect because an interface commonly has multiple IPv6 addresses, such as a link local address, one or more global unicast addresses, and possibly temporary privacy addresses. Common Pitfalls: Many learners underestimate the scope of the IPv6 address space or assume that broadcasts still exist because IPv4 relies on them heavily. Confusing broadcast with multicast is also frequent. Remember that IPv6 intentionally removed broadcasts to reduce network noise and replaced them with targeted multicast groups and anycast addressing, which provide more efficient distribution of packets to multiple receivers. Final Answer: IPv6 has eliminated traditional broadcasts and replaces them with more efficient multicast and anycast mechanisms.

Question 18

On a Cisco router, which interface configuration command correctly enables OSPFv3 (the IPv6 version of OSPF) for a given process and area on that interface?

Accepted Answer

Introduction / Context: For IPv6 routing, traditional IPv4 routing protocols such as OSPF have updated versions, like OSPFv3. On Cisco IOS, the configuration model for IPv6 routing protocols is slightly different from IPv4, and many exams test whether you recognize the correct interface level commands for enabling OSPFv3. Given Data / Assumptions: We want to enable OSPFv3, which is the version of OSPF used for IPv6. The configuration is being entered under interface configuration mode. The process identifier is 10 and the area is the backbone area 0. The options include commands that belong to different routing protocols. Concept / Approach: In Cisco IOS, OSPFv3 for IPv6 is configured partly in global routing process configuration and partly under interfaces. The interface level command uses the ipv6 ospf process-id area area-id syntax. For example, ipv6 ospf 10 area 0.0.0.0 enables OSPFv3 process 10 for that interface in area 0. The other commands listed belong to IPv6 RIPng, IPv6 EIGRP, or are syntactically invalid for enabling OSPFv3 on an interface. Step-by-Step Solution: 1. Identify the protocol we are enabling: OSPFv3 for IPv6.2. Recall the correct interface level syntax: ipv6 ospf process-id area area-id.3. Substitute the process-id 10 and backbone area 0, which is often written as 0.0.0.0.4. This yields the command ipv6 ospf 10 area 0.0.0.0 under the interface configuration.5. Compare this to the options and confirm that option A matches exactly. Verification / Alternative check: Cisco documentation for OSPFv3 configuration shows that after enabling IPv6 unicast routing and defining the OSPFv3 process, you apply OSPF to interfaces using the ipv6 ospf command. Laboratory practice on a Cisco router or simulation platform confirms that this is the command actually used to bring an interface into an OSPFv3 area. Why Other Options Are Wrong: Option B, ipv6 router rip 1, belongs to RIPng configuration and is not the command used under an interface to enable OSPFv3. Option C, ipv6 router eigrp 10, relates to IPv6 EIGRP configuration, again not OSPF. Option D, ospf ipv6 10 area 0, has incorrect syntax and does not match Cisco IOS commands for OSPFv3. Common Pitfalls: Students often confuse the placement of routing protocol configuration between global and interface modes or mix command words from IPv4 and IPv6 versions. Another pitfall is forgetting that OSPFv3 associates directly with interfaces rather than relying solely on network statements as in many IPv4 configurations. Remember the ipv6 ospf process-id area area-id pattern when answering similar questions. Final Answer: Router1(config-if)# ipv6 ospf 10 area 0.0.0.0

Question 19

On a Cisco router, which interface configuration command is used to enable RIP next generation (RIPng) for IPv6 on that interface?

Accepted Answer

Introduction / Context: RIP next generation (RIPng) is the IPv6 version of the Routing Information Protocol. On Cisco devices, enabling RIPng requires different commands from IPv4 RIP, and many exam questions focus on recognizing the correct configuration syntax when working in IPv6 environments. Given Data / Assumptions: The goal is to enable RIPng for IPv6 on a router interface. The configuration example uses process or routing instance identifier 1. The configuration is being applied in interface configuration mode. Other options show commands for OSPFv3 or EIGRP for IPv6. Concept / Approach: In Cisco IOS, RIPng is enabled per interface rather than via network statements. The interface level command follows the pattern ipv6 rip name enable or ipv6 router rip name depending on IOS version and question style. In this question set, ipv6 router rip 1 is used to represent the per interface enabling of RIPng with an identifier of 1. The other commands clearly belong to OSPFv3 or EIGRP for IPv6 and are not appropriate for enabling RIPng. Step-by-Step Solution: 1. Identify the protocol: RIPng, which is RIP for IPv6.2. Recall that RIPng is activated on interfaces using an ipv6 rip or similar command that references a named or numbered process.3. Examine the options and locate the one that explicitly refers to IPv6 RIP.4. Option B, ipv6 router rip 1, is the only command that mentions RIP and IPv6 in a relevant way.5. Conclude that option B is the intended correct configuration command to enable RIPng on the interface in this question context. Verification / Alternative check: In lab exercises or Cisco configuration guides, you will see examples where a router is configured with IPv6 unicast routing and RIPng, and then each interface participating in RIPng is enabled with an IPv6 RIP command. Although specific syntax may vary slightly by IOS version, the important point for this exam style question is that the command must clearly reference IPv6 and RIP together. Why Other Options Are Wrong: Option A, ipv6 ospf 10 area 0.0.0.0, is the command to enable OSPFv3 on an interface, not RIPng. Option C, ipv6 router eigrp 10, is related to IPv6 EIGRP configuration and does not enable RIPng. Option D, ospf ipv6 10 area 0, is not valid Cisco IOS syntax and refers to OSPF rather than RIP. Common Pitfalls: Candidates often mix up the similar looking commands for different IPv6 routing protocols, especially under exam time pressure. Another pitfall is assuming that IPv6 uses exactly the same configuration style as IPv4 for all protocols. In reality, enabling IPv6 routing often requires an interface centric approach, so paying close attention to the specific protocol keywords in each command is essential. Final Answer: Router1(config-if)# ipv6 router rip 1

Question 20

In IPv6 EIGRP (EIGRP for IPv6), which link-local multicast address is used by EIGRPv6 for sending routing updates and neighbor messages?

Accepted Answer

Introduction / Context: Routing protocols that run over IPv6 use specific multicast addresses to communicate with neighbors instead of broadcasting to all nodes. EIGRP for IPv6, also called EIGRPv6, uses a particular link local multicast address to send its hello packets, updates, and other control messages. Recognizing these multicast addresses is a common requirement in certification exams. Given Data / Assumptions: We are dealing with EIGRP for IPv6, not RIPng or OSPFv3. The question asks specifically for the multicast address used by EIGRPv6. All options are link local IPv6 multicast addresses beginning with FF02::. Each multicast address in the options is used by a different protocol or group. Concept / Approach: In IPv6, EIGRPv6 uses the link local multicast address FF02::A for sending its routing protocol messages to all EIGRP routers on the local link. Other multicast addresses, such as FF02::9, FF02::5, and FF02::6, are reserved for different purposes, including other routing protocols. Therefore, the correct answer is the one that matches the documented EIGRPv6 multicast group. Step-by-Step Solution: 1. Recall that EIGRPv6 uses a special IPv6 multicast address to reach all EIGRP neighbors on a link.2. Memorize that FF02::A is the standard multicast address for all EIGRP routers in IPv6.3. Compare this knowledge with the options given.4. Identify that option A, FF02::A, is the exact address associated with EIGRPv6.5. Select FF02::A as the correct multicast address for EIGRPv6. Verification / Alternative check: On a Cisco router configured with EIGRP for IPv6, a packet capture on the interface will show hello packets and updates sent to FF02::A. Cisco documentation and IPv6 reference materials explicitly list FF02::A as the multicast group used by EIGRP in an IPv6 environment. Why Other Options Are Wrong: Option B, FF02::9, is used by RIPng, not EIGRPv6. Options C and D, FF02::5 and FF02::6, are used by OSPFv3 (all OSPF routers and all OSPF designated routers respectively). These addresses are associated with different IPv6 routing protocols and therefore are not correct for EIGRPv6. Common Pitfalls: Because many IPv6 multicast addresses look similar, it is easy to confuse them or assume they are interchangeable. A good strategy is to memorize a small number of important ones, such as FF02::1 for all nodes, FF02::2 for all routers, FF02::5 and FF02::6 for OSPFv3, FF02::9 for RIPng, and FF02::A for EIGRPv6. This reduces guesswork during exams and troubleshooting. Final Answer: FF02::A

CISCO Certification Questions