Examkin

Tüm alıştırma soruları

1987 soru

Tüm türler1,987Çoktan seçmeli1,020Çoklu seçim452Sayısal18Eşleştirme229Sıralama203Boşluk doldurma22Kısa cevap43
Soru 1721Soru →

A network engineer needs to configure link aggregation (LAG) on a Cisco Catalyst switch connected to a Cisco AireOS Wireless LAN Controller (WLC). Arrange the following configuration steps in the correct logical order from first to last to ensure a functional static EtherChannel interface on the switch.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct order of steps is: 1. Create and enter interface configuration mode for the logical port-channel interface. 2. Configure switchport trunking encapsulation, trunk mode, and allowed VLANs on the port-channel interface. 3. Select the range of physical member interfaces connected to the WLC distribution ports. 4. Bind the physical member interfaces to the port-channel using channel-group mode on.
The correct operational sequence begins by creating the logical port-channel interface and setting its trunking and VLAN parameters. Next, the network engineer selects the physical switch interfaces connected to the controller's distribution ports and assigns them to the channel group using 'mode on'. Static aggregation is required because AireOS WLCs use unnegotiated bundle distribution across all active ports.

Adım Adım Çözüm

1
Create the logical port-channel interface on the Catalyst switch.
The port-channel interface (e.g., interface Port-channel 1) is instantiated.
Establishing the logical bundle interface first provides a central point to apply trunking properties.
2
Apply 'switchport mode trunk' and allowed VLAN commands to the port-channel interface.
The logical interface is configured as an 802.1Q trunk carrying required WLAN management and data VLANs.
Applying configurations to the port-channel interface prevents port inconsistency errors across member links.
3
Enter interface range mode for the physical switch ports connecting to the WLC.
Physical ports (e.g., interface range GigabitEthernet1/0/1 - 2) are selected.
Physical interface mode is needed to assign the specific physical links into the aggregated bundle.
4
Issue the 'channel-group 1 mode on' command on the physical interfaces.
Physical interfaces join the port-channel as static EtherChannel members.
Cisco AireOS Wireless LAN Controllers do not negotiate LACP or PAgP control frames; the switch ports must use static channel mode 'on'.

Anahtar Kavram

Switch EtherChannel Configuration Sequence for AireOS WLC Link Aggregation
Tahmini Süre:1m 30s
Soru 1722Soru →

An engineer executes the following command on router R1 to inspect an OSPFv2 interface connected to a multiaccess Ethernet segment:

text
R1# show ip ospf interface GigabitEthernet0/1
GigabitEthernet0/1 is up, line protocol is up
Internet Address 192.168.1.1/24, Area 0, Attached via Network Statement
Process ID 1, Router ID 10.1.1.1, Network Type BROADCAST, Cost: 1
Transmit Delay is 1 sec, State DROTHER, Priority 0
Designated Router (ID) 10.3.3.3, Interface address 192.168.1.3
Backup Designated router (ID) 10.2.2.2, Interface address 192.168.1.2

If the current Designated Router with Router ID 10.3.3.3 unexpectedly reboots and goes offline, which router state transition will occur on this segment?

Cevabı ve açıklamayı göster

Cevap: The router with Router ID 10.2.2.2 will automatically transition from Backup Designated Router to Designated Router.

Cevap

The router currently serving as the Backup Designated Router (Router ID 10.2.2.2) will automatically be promoted to the Designated Router role.
In OSPF broadcast multiaccess networks, when the active Designated Router (DR) fails or goes offline, the existing Backup Designated Router (BDR) is immediately promoted to become the new DR. In this output, the BDR is identified by Router ID 10.2.2.2, so it will assume the DR role.

Adım Adım Çözüm

1
Analyze the current state of OSPF routers on the broadcast segment
Router ID 10.3.3.3 is the active Designated Router (DR), Router ID 10.2.2.2 is the Backup Designated Router (BDR), and Router R1 (10.1.1.1) has Priority 0 and is in State DROTHER.
Determines the current functional roles assigned across the multiaccess network.
2
Evaluate the effect of a DR failure
When the active DR fails, OSPF non-preemptive logic mandates that the existing BDR immediately becomes the new DR to minimize downtime.
Avoids holding a full re-election for the DR position when a designated backup already exists.
3
Determine eligibility for the new BDR role
Router R1 cannot become BDR because its configured OSPF interface priority is 0.
An OSPF interface priority of 0 explicitly disqualifies a router from participating in DR/BDR elections.

Anahtar Kavram

OSPFv2 DR/BDR State Transitions and Priority 0 Exclusion
Soru 1723Soru →

A network administrator executes the command shown below to inspect the OSPFv2 configuration on interface GigabitEthernet0/0 of router R3 on a shared Ethernet segment:

text
R3# show ip ospf interface GigabitEthernet0/0
GigabitEthernet0/0 is up, line protocol is up
Internet Address 192.168.10.3/24, Area 0
Process ID 1, Router ID 192.168.10.3, Network Type BROADCAST, Cost: 1
State DROTHER, Priority 0
Designated Router (ID) 10.1.1.1, Interface address 192.168.10.1
Backup Designated Router (ID) 10.2.2.2, Interface address 192.168.10.2

If the current Designated Router (10.1.1.1) reboots and permanently disconnects from the network, which state will router R3 transition to following the OSPF election process?

Cevabı ve açıklamayı göster

Cevap: R3 will remain in the DROTHER state because an OSPF priority of 0 excludes the router from DR and BDR elections.

Cevap

Router R3 will remain in the DROTHER state because an OSPF interface priority of 0 completely disables the router from participating in DR or BDR elections.
Configuring an OSPF priority of 0 on an interface ('ip ospf priority 0') explicitly prohibits the router from participating in Designated Router (DR) and Backup Designated Router (BDR) elections on multiaccess network segments. When the primary DR fails, the existing BDR becomes the new DR, but router R3 remains a DROTHER because its priority of 0 disqualifies it from election consideration regardless of its Router ID or interface IP.

Adım Adım Çözüm

1
Analyze the CLI output for interface priority settings on router R3.
The CLI output displays 'State DROTHER, Priority 0' for interface GigabitEthernet0/0.
OSPF interface priority dictates election participation. Priority values range from 0 to 255.
2
Evaluate the effect of a priority 0 configuration during DR/BDR failover.
A priority of 0 (configured via 'ip ospf priority 0') strictly prevents the interface from becoming a DR or BDR.
Even when the existing DR fails and the current BDR moves up to DR, a router with priority 0 cannot participate in the election for the new BDR position.
3
Determine R3's resulting state after DR failover.
R3 stays in the DROTHER state while other eligible routers on the multiaccess segment contest the new BDR role.
Priority 0 overrides Router ID, Loopback IP addresses, and physical interface IP tie-breakers.

Anahtar Kavram

OSPFv2 DR/BDR Election Rules and Priority 0 Exclusion
Soru 1724Soru →

A network engineer observes that traffic from a branch office router toward destination network 172.22.0.0/16172.22.0.0/16 is taking a low-speed backup WAN link instead of the primary OSPF path. Reviewing the running configuration reveals the following static route entry configured for the backup link:

`ip route 172.22.0.0 255.255.0.0 10.0.99.2 105`

Which statement correctly explains why the backup static route is overriding the primary OSPF path?

Cevabı ve açıklamayı göster

Cevap: The configured administrative distance of 105 is lower than the default administrative distance of OSPF (110), causing the router to prefer the static route.

Cevap

The configured administrative distance of 105 is lower than the default administrative distance of OSPF (110), causing the router to prefer the static route.
Administrative distance measures route source believability on Cisco routers, where lower values are preferred. OSPF routes have a default administrative distance of 110. Because the static route was configured with an administrative distance of 105, which is lower than 110, the router installs the static route into the routing table instead of the OSPF route.

Adım Adım Çözüm

1
Identify the destination prefix and protocol Administrative Distance (AD) values
The target prefix is 172.22.0.0/16. Standard OSPF routes have a default AD of 110.
Administrative Distance ranks the trustworthiness of routing information sources.
2
Analyze the configured static route command syntax
In `ip route 172.22.0.0 255.255.0.0 10.0.99.2 105`, the trailing value 105 sets the custom Administrative Distance for this static route.
By default, static routes have an AD of 1 unless a custom value is specified at the end of the command.
3
Compare the AD of the static route against the primary protocol
Since 105<110105 < 110, the router considers the static route more trustworthy than OSPF and places it into the routing table.
Lower administrative distance values win when comparing identical destination prefixes.

Anahtar Kavram

Floating Static Route Administrative Distance
Tahmini Süre:1m 0s
Soru 1725Soru →

A network engineer is configuring Port Address Translation (PAT) on a Cisco IOS router to allow hosts on the internal private subnet 10.10.5.0/2410.10.5.0/24 to access the Internet using the router's WAN interface GigabitEthernet0/1GigabitEthernet0/1. An Access Control List (ACL 10) has already been created to permit traffic from 10.10.5.0/2410.10.5.0/24. Which two configuration steps are required on the router to complete this setup?

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: Apply the command ip nat inside on the local LAN interface and ip nat outside on interface GigabitEthernet0/1.; Issue the global configuration command ip nat inside source list 10 interface GigabitEthernet0/1 overload.

Cevap

The required steps are designating the LAN interface as inside and WAN interface as outside, and issuing the global command ip nat inside source list 10 interface GigabitEthernet0/1 overload.
To successfully establish Port Address Translation (PAT) using a router's exit interface, interfaces must be marked correctly as inside/outside boundaries, and the global NAT translation rule must reference the matching ACL along with the outside interface name and the essential 'overload' parameter.

Adım Adım Çözüm

1
Identify and configure NAT interface roles
The internal interface facing 10.10.5.0/24 is designated with 'ip nat inside', and the WAN interface GigabitEthernet0/1 is designated with 'ip nat outside'.
Cisco IOS requires traffic boundaries to be designated so it knows where translation must take place.
2
Configure the global PAT translation rule
Execute 'ip nat inside source list 10 interface GigabitEthernet0/1 overload'.
The 'overload' keyword instructs the router to translate multiple private source IP addresses onto the single IP assigned to GigabitEthernet0/1 by tracking unique source port numbers.

Anahtar Kavram

Port Address Translation (PAT) Interface Designation and Overload Syntax
Soru 1726Soru →

Place the Cisco Hot Standby Router Protocol (HSRP) router states in the correct sequential order from interface initialization to the state where the router assumes primary packet forwarding for the virtual gateway.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct sequential order of HSRP router states is: Initial State, Listen State, Speak State, Standby State, and Active State.
When HSRP is enabled on an interface, the router progresses systematically through five main states: Initial (interface up), Listen (receives Hello packets to learn virtual IP and detect peers), Speak (transmits periodic Hello packets to enter active/standby election), Standby (elected backup router), and finally Active (elected primary gateway responsible for handling virtual IP traffic).

Adım Adım Çözüm

1
Identify the state representing initial interface bring-up
Initial State is the starting point before any HSRP communication begins.
HSRP process initiates when the underlying Layer 3 interface comes up.
2
Identify the state where the router observes existing HSRP peers without transmitting
Listen State follows Initial State.
The router must first hear if active or standby routers already exist on the segment.
3
Determine when the router starts transmitting Hello packets to join the election
Speak State follows Listen State.
The router sends Hello packets to announce its presence and participate in role selection.
4
Identify the interim role prior to becoming the primary forwarder
Standby State follows Speak State.
The router acts as the designated backup router before assuming the active role if election parameters permit.
5
Identify the final operational state responsible for forwarding virtual IP traffic
Active State is the final state.
The elected active router answers ARP requests for the virtual IP and forwards user traffic.

Anahtar Kavram

HSRP State Machine Transitions
Soru 1727Soru →

Match each SNMP administrative requirement or operational workflow on the left with its corresponding SNMP version, message type, or transport characteristic on the right.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Öğeler

An agent generates an unsolicited alert that requires the receiver to send a Response PDU back to clear the notification buffer.
An NMS queries a router MIB table by requesting the next lexicographical object identifier in the hierarchy without prior knowledge of exact sub-tree indices.
A network device transmits an unacknowledged event notification using plaintext community string authentication to UDP destination port 162.
Management traffic requires SHA-256 integrity verification and AES-128 payload encryption for all polled OID data.

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

Matching pairs: 1) Unsolicited acknowledged alert -> SNMP Inform Request, 2) Sequential MIB table traversal -> SNMP GetNext Operation, 3) Unacknowledged community-based notification -> SNMPv2c Trap, 4) Authentication and encryption model -> SNMPv3 authPriv Security Level.
Each match accurately reflects standard Cisco SNMP protocol behaviors: SNMP Informs require receiver acknowledgements via Response PDUs; SNMP GetNext requests iteratively traverse MIB instances sequentially; SNMPv2c Traps send unacknowledged alerts over UDP port 162 using community strings; and SNMPv3 authPriv enforces both authentication hashing and data encryption.

Adım Adım Çözüm

1
Differentiate notification reliability mechanics.
Identify that Informs require explicit NMS acknowledgement via a Response PDU, whereas Traps are unacknowledged fire-and-forget notifications sent to UDP 162.
Relates the requirement for receiver verification to the SNMP Inform mechanism and unacknowledged delivery to SNMP Traps.
2
Analyze MIB polling operation types.
Recognize that walking or retrieving contiguous MIB variables without knowing explicit instance index values uses the GetNext PDU.
GetNext inspects the lexicographical MIB tree structure sequentially.
3
Evaluate SNMPv3 security model features.
Match the combination of message hashing (authentication) and payload encryption (privacy) directly to the authPriv security level.
SNMPv3 defines three security levels: noAuthNoPriv (none), authNoPriv (authentication only), and authPriv (both authentication and privacy encryption).

Anahtar Kavram

SNMP Messaging Mechanics, MIB Traversal, and SNMPv3 Security Models
Soru 1728Soru →

A network administrator is manually configuring Rapid PVST+ on a Cisco Catalyst switch to act as a secondary root bridge for VLAN 75. The administrator attempts to enter a custom priority value using the `spanning-tree vlan 75 priority <value>` command in global configuration mode. Which priority value will be accepted by Cisco IOS for this command?

Cevabı ve açıklamayı göster

Cevap: 28672

Cevap

The priority value 28672 is accepted because Cisco IOS requires the priority argument in the 'spanning-tree vlan X priority' command to be specified in increments of 4096.
In Rapid PVST+, Cisco switches enforce the 802.1t System ID Extension. The 16-bit Priority field is split into a 4-bit Bridge Priority field and a 12-bit VLAN ID field. Consequently, the user-configurable base bridge priority in the CLI must be an explicit multiple of 4096 (4096×7=286724096 \times 7 = 28672). When 28672 is entered, the switch adds VLAN 75 internally to yield a total priority of 28747.

Adım Adım Çözüm

1
Identify the standard requirement for Rapid PVST+ Bridge Priority values in Cisco IOS.
Rapid PVST+ utilizes 802.1t System ID Extension, dividing the 16-bit Bridge Priority field into a 4-bit Priority field and a 12-bit System ID Extension (VLAN ID).
Because the upper 4 bits control the configurable priority, configured values must be multiples of 212=40962^{12} = 4096.
2
Evaluate the CLI input requirements for the command 'spanning-tree vlan 75 priority <value>'.
The CLI argument accepts only base priority increments: 0, 4096, 8192, 12288, 16384, 20480, 24576, 28672, 32768, etc.
The switch software automatically appends the VLAN ID (75) to the base priority to form the actual 16-bit priority carried in BPDUs (28672+75=2874728672 + 75 = 28747).
3
Select the option that represents a valid 4096 multiple.
28672 is equal to 4096×74096 \times 7, making it a valid configuration parameter.
All other choices represent non-4096 multiples or values resulting from manually pre-adding the VLAN ID.

Anahtar Kavram

Rapid PVST+ System ID Extension and Bridge Priority CLI configuration constraints.
Soru 1729Soru →

Match each enterprise security threat scenario on the left with its most effective primary mitigation strategy on the right.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Öğeler

Password Spray Attack attempting low-frequency authentication across hundreds of corporate accounts
Man-in-the-Middle (MitM) eavesdropping on unencrypted transit traffic across an untrusted network segment
Spear Phishing campaign directing executive targets to a spoofed login portal
Zero-Day software vulnerability targeting an unpatched network management daemon

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

Password Spray Attack matches Multi-Factor Authentication (MFA) and smart lockout policies. Man-in-the-Middle eavesdropping matches end-to-end cryptographic transport protocols (TLS/IPsec). Spear Phishing matches email authentication standards (SPF/DKIM/DMARC) and user training. Zero-Day software vulnerability matches vendor micro-segmentation, IPS signatures, and rapid patching.
Each threat targets a specific layer or operational vulnerability, requiring an aligned mitigation control: Password Spraying is countered by Multi-Factor Authentication; Man-in-the-Middle transit interception is countered by TLS/IPsec encryption; Spear Phishing is countered by SPF/DKIM/DMARC and security awareness; and Zero-Day software flaws are countered by IPS signatures, network segmentation, and prompt patching.

Adım Adım Çözüm

1
Analyze the Password Spray threat vector.
Identify that password spraying avoids single-account lockout by trying one password against many accounts.
MFA is the primary defense because even if a password matches, login fails without the second factor.
2
Analyze the Man-in-the-Middle (MitM) threat vector.
Identify that MitM exploits cleartext communication channels.
Cryptographic transport protocols like TLS and IPsec encrypt payload data and verify server identity via certificates.
3
Analyze the Spear Phishing threat vector.
Identify that spear phishing uses targeted fraudulent emails to fool specific personnel.
Combining domain verification controls (SPF/DKIM/DMARC) with human security training reduces email spoofing and link clicking.
4
Analyze the Zero-Day vulnerability threat vector.
Identify that zero-day exploits target unpatched software weaknesses.
Deploying IPS signatures, micro-segmentation, and timely vendor security patches directly mitigates software vulnerability risks.

Anahtar Kavram

Threat, Vulnerability, and Mitigation Mapping
Soru 1730Soru →

Match each OSPFv2 interface scenario or configuration on the left to its corresponding election behavior or operational characteristic on the right.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Öğeler

Interface configured with `ip ospf network broadcast`
Interface configured with `ip ospf network point-to-point`
Interface configured with `ip ospf priority 0` on a multiaccess link
Router with priority 255 added to a link with an active, established DR

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

Interface configured with `ip ospf network broadcast` matches 'Performs DR/BDR elections and uses default Hello/Dead timers of 10s and 40s.'
Interface configured with `ip ospf network point-to-point` matches 'Establishes neighbor adjacencies without electing a DR/BDR using 10s/40s timers.'
Interface configured with `ip ospf priority 0` on a multiaccess link matches 'Permanently remains a DROTHER and is excluded from DR/BDR election.'
Router with priority 255 added to a link with an active, established DR matches 'Fails to take over the DR role due to the non-preemptive nature of OSPF elections.'
Each OSPF interface setting dictates specific operational properties: Broadcast links use 10s/40s timers and elect DR/BDR; Point-to-Point links use 10s/40s timers without electing DR/BDR; Priority 0 prevents any DR/BDR candidacy resulting in DROTHER status; and DR/BDR elections are non-preemptive, preventing new higher-priority routers from taking over an active DR role.

Adım Adım Çözüm

1
Analyze OSPF network type behaviors regarding DR/BDR election requirement.
Broadcast networks elect a DR and BDR to reduce adjacency overhead over multiaccess media. Point-to-point networks connect exactly two routers and omit the DR/BDR election process entirely.
DR/BDR selection depends on the underlying OSPF network type setting.
2
Evaluate the effect of interface priority configuration.
Setting `ip ospf priority 0` explicitly removes a router from participating in DR or BDR election, locking its state as DROTHER.
Priority values range from 0 to 255, where 0 represents absolute exclusion from election eligibility.
3
Determine election preemption behavior when topology changes occur.
OSPF elections are non-preemptive; an existing DR retains its role even if a router with a higher priority (such as 255) joins the network after election completion.
Non-preemption prevents network instability and continuous routing recalculations upon router reboots or link flaps.

Anahtar Kavram

OSPFv2 Network Types, Interface Priority, and Election Preemption Rules
Soru 1731Soru →

A security analyst is reviewing measures to enforce the Confidentiality, Integrity, and Availability (CIA) triad across an enterprise network. Which of the following security controls directly address the Integrity leg of the CIA triad? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: Applying cryptographic hash functions (such as SHA-256) to verify system configuration files; Utilizing asymmetric digital signatures to validate the authenticity and unmodified state of software updates

Cevap

Cryptographic hash functions (such as SHA-256) and digital signatures directly enforce data Integrity by detecting unauthorized modifications.
Data Integrity ensures that information is accurate and unaltered during storage or transit. Using SHA-256 cryptographic hashing allows systems to verify file content against expected checksums. Digital signatures use hashing combined with public key infrastructure to ensure software updates remain unaltered and authentic.

Adım Adım Çözüm

1
Define the Integrity component of the CIA triad.
Integrity ensures that network data and system configurations remain accurate, complete, and protected against unauthorized modification or tampering.
Security controls for integrity must detect or prevent unauthorized alterations to data.
2
Evaluate mechanisms that protect or verify data against alteration.
SHA-256 hashing generates a unique checksum to detect file changes, and digital signatures verify both sender identity and content immutability.
Both techniques specifically address data tampering and change detection.

Anahtar Kavram

CIA Triad - Integrity Security Controls
Soru 1732Soru →

Place the following operational steps in the correct chronological order to show how a Cisco router configured as a DHCP relay agent processes an incoming client discovery message.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct sequence begins with the host client broadcasting a DHCP DISCOVER packet on its local subnet. Next, the local router interface receives the broadcast packet and evaluates the configured ip helper-address. The router then inserts its local receiving interface IP address into the Gateway IP Address (giaddr) field. Finally, the router converts the packet to a unicast IP packet and forwards it to the target DHCP server address.
When an unconfigured host requests an IP address, it broadcasts a DHCP DISCOVER frame. The local router interface intercepts this broadcast, modifies the DHCP header by adding its receiving interface IP to the giaddr field, and changes the destination from broadcast to unicast directed at the configured DHCP server IP.

Adım Adım Çözüm

1
Identify the client-side initiation of the DHCP process.
The host client generates a broadcast DHCP DISCOVER message.
Unconfigured hosts must use broadcast addressing to discover available DHCP servers on the local segment.
2
Determine the initial reception step by the relay agent.
The router interface captures the broadcast and checks for an active ip helper-address statement.
The ip helper-address command instructs the interface to process incoming UDP port 67 broadcast traffic.
3
Identify the mandatory payload modification performed by the relay agent.
The router writes its own interface IP into the packet's giaddr field.
Without the giaddr field populated, the central server cannot determine which pool and subnet address range to offer.
4
Determine the final packet forwarding operation.
The router forwards the modified DHCP request as a unicast packet to the central DHCP server.
Broadcasts are not routed by default; relaying requires converting the frame into a unicast transmission targeting the DHCP server.

Anahtar Kavram

DHCP Relay Agent Operation and Payload Modification (giaddr)
Tahmini Süre:45s
Soru 1733Soru →

A network engineer is provisioning host IP addresses within the enterprise subnet block 192.168.48.0/20192.168.48.0/20. Which of the following IP addresses are valid usable host addresses for endpoints on this subnetwork? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: 192.168.50.100192.168.50.100; 192.168.63.254192.168.63.254

Cevap

The addresses 192.168.50.100192.168.50.100 and 192.168.63.254192.168.63.254 are valid usable host addresses within the 192.168.48.0/20192.168.48.0/20 subnet.
For the prefix /20/20, the third octet increments in blocks of 16 (256−240=16256 - 240 = 16). For the subnet starting at 192.168.48.0192.168.48.0, the subnet range spans from 192.168.48.0192.168.48.0 to 192.168.63.255192.168.63.255. Subtracting the network ID (192.168.48.0192.168.48.0) and broadcast ID (192.168.63.255192.168.63.255) leaves a usable host range of 192.168.48.1192.168.48.1 through 192.168.63.254192.168.63.254. Therefore, 192.168.50.100192.168.50.100 and 192.168.63.254192.168.63.254 are valid host assignments.

Adım Adım Çözüm

1
Determine the subnet mask block size for the /20 prefix length.
A /20/20 prefix corresponds to a subnet mask of 255.255.240.0255.255.240.0. The block size in the third octet is 256−240=16256 - 240 = 16.
Prefix length /20/20 uses 4 subnet bits in the third octet (128+64+32+16=240128 + 64 + 32 + 16 = 240).
2
Identify the network address and broadcast address boundaries.
Subnet Network ID: 192.168.48.0192.168.48.0. Next Subnet ID: 192.168.64.0192.168.64.0. Broadcast Address: 192.168.63.255192.168.63.255.
Adding the block size of 16 to the third octet start (48+1648 + 16) gives the next subnet boundary at 192.168.64.0192.168.64.0.
3
Calculate the usable host address range.
Usable host range: 192.168.48.1192.168.48.1 to 192.168.63.254192.168.63.254.
Usable hosts exclude the network ID (192.168.48.0192.168.48.0) and broadcast address (192.168.63.255192.168.63.255).
4
Evaluate the choices against the usable host address range.
192.168.50.100192.168.50.100 and 192.168.63.254192.168.63.254 fall within the usable range, whereas 192.168.48.0192.168.48.0 (network ID) and 192.168.63.255192.168.63.255 (broadcast ID) are reserved.
Only IP addresses between the first host and last host can be assigned to endpoint interfaces.

Anahtar Kavram

IPv4 Subnet Boundaries and Usable Host Range Calculation
Tahmini Süre:1m 30s
Soru 1734Soru →

A network administrator configures HSRP group 10 on two switches, R1 and R2, to provide gateway redundancy for VLAN 20. R1 is configured with a priority of 115, preemption enabled, and tracks interface GigabitEthernet0/1 with a priority decrement of 20. R2 is configured with a priority of 105, but preemption is disabled on R2. Initially, all interfaces are operational, and R1 is the Active router. If interface GigabitEthernet0/1 on R1 fails, which router will fulfill the Active role for HSRP group 10, and why?

Cevabı ve açıklamayı göster

Cevap: R1 remains the Active router because R2 does not have preemption enabled, even though R1's operational priority drops to 95.

Cevap

R1 remains the Active router because preemption is not enabled on R2, preventing it from taking over despite having a higher operational priority.
In HSRP, when an active router's tracked interface fails, its priority is decremented (115 - 20 = 95). Even though the standby router has a higher priority (105 > 95), it cannot claim the Active role unless preemption ('standby preempt') is explicitly configured on the standby router itself. Therefore, the current Active router remains Active.

Adım Adım Çözüm

1
Calculate R1's operational priority after the tracked interface failure.
Initial priority (115) minus decrement (20) equals operational priority 95.
Interface tracking reduces the active router's HSRP priority upon tracked link failure.
2
Compare the operational priorities of R1 and R2.
R1 operational priority is 95; R2 priority is 105.
R2 now possesses a higher numeric priority than R1.
3
Evaluate preemption settings on the standby router (R2).
R2 does not have preemption enabled.
In HSRP, a standby router with a higher priority will NOT seize the Active role from an existing Active router unless 'standby preempt' is explicitly configured on the standby router.

Anahtar Kavram

HSRP Preemption Mechanics and Interface Tracking
Soru 1735Soru →

A network operations center engineer is reviewing syslog messages emitted by a Cisco IOS router. Arrange the following syslog events in order from HIGHEST severity (lowest numerical severity level) to LOWEST severity (highest numerical severity level).

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct sequence from highest severity (lowest numeric value) to lowest severity (highest numeric value) is: 1) Hardware watchdog system failure (Level 0 - Emergency), 2) Duplex mismatch error (Level 3 - Error), 3) Configuration commit notice (Level 5 - Notice), 4) Syslog server initialization message (Level 6 - Informational), and 5) Debug packet trace output (Level 7 - Debugging).
The correct ordering aligns with the standard Cisco IOS Syslog numerical severity scale: 0 (Emergency), 1 (Alert), 2 (Critical), 3 (Error), 4 (Warning), 5 (Notice), 6 (Informational), and 7 (Debugging). The hardware failure message is Emergency (Level 0), followed by interface error (Level 3), configuration change (Level 5), syslog service initialization (Level 6), and debug packet trace output (Level 7).

Adım Adım Çözüm

1
Determine the numerical severity code assigned to each Cisco IOS event category in the Syslog standard.
System failure = Level 0 (Emergency); Duplex mismatch = Level 3 (Error); Configuration commit = Level 5 (Notice); Syslog host initialization = Level 6 (Informational); Debug packet trace = Level 7 (Debugging).
Cisco IOS categorizes log severity from Level 0 (most critical) through Level 7 (least critical).
2
Order the identified events in ascending numerical order of their severity levels.
The numerical order is 0 -> 3 -> 5 -> 6 -> 7.
A lower numerical severity level corresponds to a higher criticality event in Syslog architecture.

Anahtar Kavram

Cisco IOS Syslog severity level taxonomy (0-Emergency to 7-Debugging)
Soru 1736Soru →

An IT technician is preparing a newly racked Cisco Catalyst switch to connect corporate workstations. The technician needs to create VLAN 15 named FIN_DEPT and assign interface GigabitEthernet0/5 to this VLAN as a static access port while explicitly disabling Dynamic Trunking Protocol (DTP) frame negotiation. Which sequence of Cisco IOS commands correctly accomplishes this configuration?

Cevabı ve açıklamayı göster

Cevap: vlan 15
name FIN_DEPT
exit
interface GigabitEthernet0/5
switchport mode access
switchport access vlan 15
switchport nonegotiate

Cevap

The correct command sequence creates VLAN 15 named FIN_DEPT, configures the interface with 'switchport mode access' to force static access mode, assigns it to VLAN 15 with 'switchport access vlan 15', and disables DTP frame negotiation using 'switchport nonegotiate'.
The correct command sequence creates VLAN 15 named FIN_DEPT in global configuration mode, enters interface mode for GigabitEthernet0/5, sets the operational mode to static access using 'switchport mode access', assigns it to VLAN 15 using 'switchport access vlan 15', and turns off Dynamic Trunking Protocol frame generation with 'switchport nonegotiate'.

Adım Adım Çözüm

1
Create and name the VLAN in global configuration mode
VLAN 15 is created and assigned the name FIN_DEPT.
VLANs must exist in the switch VLAN database to forward traffic properly for assigned access interfaces.
2
Enter interface configuration mode and set the switchport mode
Interface GigabitEthernet0/5 is statically set to access mode via 'switchport mode access'.
Static access mode prevents the port from dynamically negotiating trunking.
3
Assign the interface to VLAN 15 and disable DTP negotiation
The port is assigned to VLAN 15 with 'switchport access vlan 15' and DTP negotiation is disabled with 'switchport nonegotiate'.
This completes static access port setup and hardens the port against unauthorized trunk negotiation.

Anahtar Kavram

VLAN Creation, Access Port Assignment, and DTP Hardening
Soru 1737Soru →

Clients connected to VLAN 10 successfully receive dynamic IP addresses from a remote server located at 192.168.100.50, but clients on VLAN 20 fail to obtain IP addresses and assign themselves 169.254.x.x addresses.

An engineer inspects the running configuration of router R1:

text
interface GigabitEthernet0/0.10
encapsulation dot1Q 10
ip address 10.10.10.1 255.255.255.0
ip helper-address 192.168.100.50
!
interface GigabitEthernet0/0.20
encapsulation dot1Q 20
ip address 10.10.20.1 255.255.255.0
!
interface GigabitEthernet0/1
description Connection to DHCP Server Subnet
ip address 192.168.100.1 255.255.255.0
ip helper-address 192.168.100.50

Which configuration change on router R1 will restore DHCP functionality for clients on VLAN 20?

Cevabı ve açıklamayı göster

Cevap: Remove the helper address command from interface GigabitEthernet0/1 and add ip helper-address 192.168.100.50 under subinterface GigabitEthernet0/0.20.

Cevap

Remove the helper address configuration from interface GigabitEthernet0/1 and configure ip helper-address 192.168.100.50 under subinterface GigabitEthernet0/0.20.
To relay DHCP broadcast requests from clients to a server on a different subnet, the Cisco IOS `ip helper-address <server-ip>` command must be configured on the client-facing layer 3 interface (subinterface GigabitEthernet0/0.20). In the provided scenario, subinterface GigabitEthernet0/0.20 is missing the command, while interface GigabitEthernet0/1 mistakenly has it configured. Moving the command to GigabitEthernet0/0.20 allows R1 to intercept VLAN 20 broadcast DISCOVER messages, insert 10.10.20.1 as the gateway address (GIADDR), and unicast the request to 192.168.100.50.

Adım Adım Çözüm

1
Analyze client-to-relay path requirements
DHCP DISCOVER packets generated by clients are local Layer 2 broadcasts targeted to UDP port 67.
Routers drop Layer 2/Layer 3 broadcast packets by default and do not forward them between interfaces or subinterfaces.
2
Identify correct placement of the ip helper-address command
The `ip helper-address` command must be applied to the incoming (ingress) interface where client broadcasts originate (GigabitEthernet0/0.20).
When applied on the client interface, the router intercepts UDP broadcast traffic, populates the GIADDR field with the interface's IP address (10.10.20.1), and unicasts the packet to the specified DHCP server.
3
Evaluate the current flawed configuration on R1
Subinterface GigabitEthernet0/0.20 lacks `ip helper-address`, while the egress interface GigabitEthernet0/1 has an unnecessary `ip helper-address` configured.
Configuring `ip helper-address` on the egress interface towards the server does nothing for clients on VLAN 20 because client broadcasts enter on subinterface GigabitEthernet0/0.20 and are dropped before reaching interface GigabitEthernet0/1.

Anahtar Kavram

DHCP Relay Agent Configuration and Placement
Tahmini Süre:1m 30s
Soru 1738Soru →

An administrator configures dynamic NAT on a Cisco IOS router using a pool containing a single public IP address (203.0.113.100203.0.113.100) to enable Internet connectivity for internal workstations. During testing, only the first internal user who initiates outbound traffic can access external sites. All subsequent attempts from other internal users to access the Internet fail. Which action on the router resolves this connectivity issue?

Cevabı ve açıklamayı göster

Cevap: Append the `overload` keyword to the `ip nat inside source list <ACL> pool <POOL>` configuration command.

Cevap

Append the `overload` keyword to the global `ip nat inside source list <ACL> pool <POOL>` command to enable Port Address Translation (PAT).
When dynamic NAT is configured with an IP NAT pool containing a single public IP address, omitting the `overload` keyword restricts translations to a single 1-to-1 mapping. Once the first host initiates traffic, the single address in the pool is exhausted. Appending the `overload` keyword enables Port Address Translation (PAT), allowing multiple internal hosts to share the single IP address concurrently by tracking unique Layer 4 source port numbers.

Adım Adım Çözüm

1
Analyze the symptom of dynamic NAT failure.
Without port translation enabled, dynamic NAT allocates pool IP addresses on a strict 1-to-1 basis. With a single public IP address in the pool, only one internal host receives a translation entry.
Determines why subsequent internal hosts fail to obtain an outbound translation.
2
Identify the required feature for many-to-one translation using a single IP address.
Port Address Translation (PAT) allows thousands of internal hosts to multiplex outbound connections over a single IP address using unique TCP/UDP source ports.
PAT is activated on Cisco IOS dynamic NAT configurations by appending the `overload` keyword.
3
Select the correct command modification.
Modifying the translation statement to include `overload` (`ip nat inside source list <ACL> pool <POOL> overload`) resolves the single-host limitation.
Applies PAT, enabling all internal hosts to share the single public IP address concurrently.

Anahtar Kavram

Port Address Translation (PAT) Overload Configuration
Soru 1739Soru →

An enterprise organization suffers a security incident where an unauthorized actor intercepts and alters router configuration files in transit across an unencrypted network link, causing network routing tables to become corrupted. The security team must implement controls to ensure that data cannot be modified in transit without detection. Which core principle of the CIA triad was violated during this attack, and which security mechanism directly mitigates this specific vulnerability?

Cevabı ve açıklamayı göster

Cevap: Integrity was violated; it is mitigated by implementing cryptographic message hashing and digital signatures.

Cevap

Integrity was violated; it is mitigated by implementing cryptographic message hashing and digital signatures.
The security incident involved the unauthorized modification of data in transit. In the CIA triad, protecting data against unauthorized alteration or tampering is the core requirement of Integrity. To mitigate this threat, cryptographic mechanisms such as message hashing (e.g., HMAC) and digital signatures are deployed to detect any payload tampering.

Adım Adım Çözüm

1
Analyze the nature of the security incident described in the scenario.
The attacker intercepted and modified configuration files in transit, corrupting routing tables.
Identifying whether data was disclosed, modified, or rendered unavailable determines which CIA triad pillar was breached.
2
Map the incident characteristics to the CIA Triad (Confidentiality, Integrity, Availability).
Unauthorized modification of data in transit is a breach of Integrity.
Integrity guarantees that information is authentic and protected against unauthorized alteration or tampering.
3
Determine the appropriate security mitigation mechanism for preserving Integrity.
Cryptographic hashing algorithms (such as SHA-256) and digital signatures verify data authenticity and detect tampering.
Hashing produces a unique checksum that changes if even a single bit of data is altered during transmission.

Anahtar Kavram

CIA Triad Principles and Integrity Verification Mitigations
Soru 1740Soru →

An enterprise network administrator discovers a weakness in a router's firmware that has not yet been patched by the vendor. This weakness could potentially allow unauthorized access if targeted by malicious traffic. Which security term specifically describes this software weakness?

Cevabı ve açıklamayı göster

Cevap: Vulnerability

Cevap

Vulnerability best describes an unpatched software weakness or flaw in system firmware.
The term vulnerability specifically refers to any weakness, flaw, or bug in system design, implementation, or firmware that leaves it open to attack.

Adım Adım Çözüm

1
Analyze the item description
The scenario describes a software flaw/weakness present in router firmware.
Security terminology distinguishes between the flaw itself, the potential attacker, the mechanism of attack, and the overall business impact.
2
Map to fundamental security definitions
A weakness or flaw in system software/hardware is defined as a Vulnerability.
Threats act upon vulnerabilities using exploits, resulting in risk to the organization.

Anahtar Kavram

Key Security Definitions: Vulnerability vs. Threat vs. Exploit vs. Risk
ÖncekiSayfa 87 / 100Sonraki
Tüm alıştırma soruları — Cisco CCNA | Examkin