Tüm alıştırma soruları

2237 soru

Tüm türler2,237 Çoktan seçmeli1,150 Çoklu seçim488 Sayısal30 Eşleştirme350 Sıralama201 Kısa cevap18

Soru 1961Soru →

A network engineering team is designing a disaster recovery architecture for a multi-tier financial portal. The business impact analysis mandates a Recovery Point Objective (RPO) of near-zero seconds for transactional data and a Recovery Time Objective (RTO) of under 2 hours for all network services. Which TWO of the following technical controls must be combined to satisfy these operational requirements?

Geçerli olan tümünü seçin

Implementation of real-time synchronous database replication across geographically distinct data centers

Deployment of an active-hot recovery site with pre-configured infrastructure and automated global server load balancing

Execution of hourly incremental backups coupled with night-time full system snapshots stored offsite

Maintenance of a cold site equipped with space and power contracts for rapid hardware delivery

Daily differential backups combined with weekly full bare-metal server images

Cevabı ve açıklamayı göster

Cevap: Implementation of real-time synchronous database replication across geographically distinct data centers; Deployment of an active-hot recovery site with pre-configured infrastructure and automated global server load balancing

Cevap

The correct controls are real-time synchronous database replication across data centers and the deployment of an active-hot recovery site with automated global server load balancing.

To satisfy a near-zero RPO, data must be replicated immediately as transactions occur, which requires synchronous replication. To satisfy an RTO of under 2 hours, network infrastructure must already be live and synchronized in a hot site configuration with automatic global load balancing to redirect user sessions instantly.

Adım Adım Çözüm

Analyze the RPO requirement

Near-zero seconds RPO means no data loss can occur during a failover event.

Asynchronous or scheduled backups (such as hourly or daily backups) leave a window where un-backed-up data will be lost. Synchronous replication ensures data is committed to both locations simultaneously before acknowledging transaction completion.

Analyze the RTO requirement

RTO under 2 hours requires rapid infrastructure availability and traffic redirection.

Cold or warm sites require extended operational ramp-up times (procuring hardware, restoring images, mounting tape backups). An active-hot site maintains mirrored hardware and live networking assets, enabling automated GSLB failover well within the 2-hour window.

Anahtar Kavram

RTO and RPO Alignment with Site Selection and Replication Mechanisms

Soru 1962Soru →

Match each IEEE 802.11 wireless standard with its corresponding operating frequency bands, maximum channel bonding capabilities, and key technological features.

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Cevap

IEEE 802.11g pairs with

2.4\text{ GHz}

OFDM at

54\text{ Mbps}

; IEEE 802.11n pairs with dual-band MIMO and

40\text{ MHz}

channels; IEEE 802.11ac pairs with

5\text{ GHz}

-only operation, 256-QAM, and

160\text{ MHz}

channels; IEEE 802.11ax pairs with multi-band operation, OFDMA, and BSS coloring.

Each Wireless standard maps directly to its core specifications: 802.11g provides

54\text{ Mbps}

via OFDM in

2.4\text{ GHz}

; 802.11n introduces dual-band MIMO and

40\text{ MHz}

channel bonding; 802.11ac operates strictly in

5\text{ GHz}

with 256-QAM up to

160\text{ MHz}

channel width; and 802.11ax introduces OFDMA, BSS coloring, and TWT for high-density environments across

2.4

5

, and

6\text{ GHz}

frequencies.

Adım Adım Çözüm

Identify legacy single-band

2.4\text{ GHz}

standards using basic OFDM.

IEEE 802.11g provides up to

54\text{ Mbps}

in the

2.4\text{ GHz}

band.

802.11g was designed as an upgrade to 802.11b on the

2.4\text{ GHz}

spectrum.

Identify the standard that introduced MIMO spatial streams and dual-band flexibility.

IEEE 802.11n (Wi-Fi 4) supports both

2.4\text{ GHz}

and

5\text{ GHz}

with

40\text{ MHz}

channels.

802.11n was the first standard to leverage multiple antennas (MIMO) and

40\text{ MHz}

bonded channels across both bands.

Differentiate 802.11ac from 802.11ax by operating frequencies and modulation techniques.

802.11ac operates exclusively in

5\text{ GHz}

with 256-QAM and

160\text{ MHz}

bonding, whereas 802.11ax works on

2.4/5/6\text{ GHz}

with OFDMA.

802.11ac focuses on high throughput in

5\text{ GHz}

, while 802.11ax focuses on multi-band spectral efficiency with OFDMA.

Anahtar Kavram

Wireless Standards and Specifications

Soru 1963Soru →

A network technician is troubleshooting an issue where a newly connected workstation on VLAN 30 fails to receive an IP address from a central DHCP server located on VLAN 10. Place the troubleshooting steps in the correct logical sequence according to standard network troubleshooting methodology to isolate and resolve the issue.

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Cevap

The correct logical order begins with Layer 1 physical link verification, followed by local client IP configuration inspection, then router DHCP relay (ip helper-address) verification, and lastly central DHCP server scope pool check.

The correct sequence follows standard structured troubleshooting: starting at the physical layer (verifying link LED), checking local operating system network configuration (confirming APIPA), inspecting intermediate network infrastructure (verifying IP helper/DHCP relay placement across VLAN boundaries), and finally validating end-service resource capacity (DHCP scope pool status).

Adım Adım Çözüm

Verify physical connection and port status.

Physical link is active and connected.

Always verify basic layer 1 connectivity before diagnosing software or protocol issues.

Inspect local network adapter status on the client.

Client displays an APIPA address (169.254.x.x).

Confirms that the host attempted DHCP discovery but received no response.

Verify the DHCP relay configuration on the VLAN 30 gateway interface.

Ensures DHCP broadcast packets are converted to unicast and forwarded to the server on VLAN 10.

Routers drop broadcast packets by default; without a relay agent, DHCP traffic cannot cross subnets.

Check the central DHCP server scope status for VLAN 30.

Determines whether available leases exist in the scope.

If relaying is operational, scope exhaustion is the next common failure point.

Anahtar Kavram

Inter-VLAN DHCP Troubleshooting Methodology

Soru 1964Soru →

A network technician is troubleshooting a client workstation that cannot access an internal web portal by its fully qualified domain name (FQDN). Following a standard bottom-up troubleshooting workflow to isolate network issues from local network configuration to name resolution, place the following command-line steps in the correct logical diagnostic sequence.

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Cevap

The correct sequence begins with checking local interface settings using ipconfig /all, testing local subnet routing using ping to the default gateway, testing remote host IP reachability using ping to the target IP, and finally diagnosing DNS name resolution using nslookup.

The logical sequence follows standard CompTIA network troubleshooting: first, check local host configuration using ipconfig /all; second, verify local subnet network reachability by pinging the default gateway IP; third, verify end-to-end network path reachability by pinging the destination server's IP address directly; fourth, test domain name lookup functionality using nslookup to confirm FQDN-to-IP mapping.

Adım Adım Çözüm

Inspect local network configuration

The technician verifies the local IP parameters (IP address, subnet mask, default gateway, DNS server) using ipconfig /all.

This confirms basic NIC operational status and verifies assigned IP configuration settings.

Test local router reachability

The technician issues ping 192.168.1.1 to test connectivity to the local gateway router.

Pinging the default gateway confirms local link layer and Layer 3 subnet connectivity.

Test end-to-end IP routing reachability

The technician executes ping 10.0.5.25 using the target server's raw IP address.

Directly pinging the destination IP tests end-to-end routing without relying on domain name resolution.

Diagnose host name resolution

The technician uses nslookup portal.lab.internal to evaluate FQDN query responses from the DNS server.

Performing an explicit DNS lookup isolates application layer name resolution problems after IP reachability is confirmed.

Anahtar Kavram

Command-Line Troubleshooting Methodology & Tool Selection

Soru 1965Soru →

A network administrator is troubleshooting an issue where workstation users are directed to an old server IP address for an internal web application hosted at `app.corp.internal`. The administrator suspects the local DNS server (`192.168.1.1`) is returning a cached, non-authoritative record. Which command should the administrator run to query the authoritative DNS server at `10.100.1.10` directly for the IPv4 address record?

nslookup app.corp.internal 10.100.1.10

dig -t AAAA app.corp.internal @10.100.1.10

nslookup -port=80 app.corp.internal 10.100.1.10

dig app.corp.internal -server 10.100.1.10

Cevabı ve açıklamayı göster

Cevap: nslookup app.corp.internal 10.100.1.10

Cevap

The command `nslookup app.corp.internal 10.100.1.10` directly queries the authoritative DNS server for the standard IPv4 address (A record) of the specified host.

The command `nslookup app.corp.internal 10.100.1.10` instructs `nslookup` to send a default IPv4 (A record) lookup query for `app.corp.internal` directly to the specified server address `10.100.1.10`, bypassing the host's default configured DNS server.

Adım Adım Çözüm

Identify the required utility and target host name.

The target domain to resolve is `app.corp.internal` for standard IPv4 resolution (A record).

The administrator needs to verify the IPv4 mapping returned directly by the authoritative server.

Determine the proper syntax to bypass the default local resolver.

Appending `10.100.1.10` after the hostname in `nslookup` sends the query directly to `10.100.1.10`.

This bypasses cached or non-authoritative entries stored on the local DNS server (`192.168.1.1`).

Verify command flags and protocol ports.

`nslookup app.corp.internal 10.100.1.10` uses standard DNS port 53 and queries for an A record by default.

No additional flags altering port numbers or record types to IPv6 are needed.

Anahtar Kavram

Direct DNS Querying via Command-Line Utilities

Soru 1966Soru →

A network administrator is setting up a new server on a subnet designed for database hosts: $172.16.10.128/26$ . The default gateway router interface for this subnet is assigned IP address $172.16.10.129/26$ . The administrator manually configures the server with IP address $172.16.10.66$ and subnet mask $255.255.255.192$ ( $/26$ ). Upon testing, the server cannot ping its default gateway or reach any external networks. Which of the following best identifies the root cause of this connectivity failure?

The host IP address assigned to the server resides on a different IP subnet than the default gateway.

The server failed to receive a DHCP lease and automatically assigned itself an Automatic Private IP Addressing (APIPA) address.

The local router switchport is missing an IP helper address configuration to forward DHCP broadcast requests.

The IP address assigned to the default gateway is the reserved network broadcast address for the subnet.

Cevabı ve açıklamayı göster

Cevap: The host IP address assigned to the server resides on a different IP subnet than the default gateway.

Cevap

The host IP address assigned to the server resides on a different IP subnet than the default gateway.

With a

/26

subnet mask (

255.255.255.192

), subnets increment in blocks of 64 addresses. The default gateway IP

172.16.10.129

resides in the

172.16.10.128/26

subnet (usable host range

172.16.10.129 - 172.16.10.190

). However, the static host IP

172.16.10.66

resides in the adjacent

172.16.10.64/26

subnet (usable host range

172.16.10.65 - 172.16.10.126

). Because the host and default gateway are on different logical IP subnets, the host cannot complete ARP resolution for the default gateway IP address, resulting in total unreachability.

Adım Adım Çözüm

Analyze the subnet boundaries for a /26 subnet mask (255.255.255.192).

A /26 mask creates subnets with block sizes of 64 addresses: 172.16.10.0/26 (0-63), 172.16.10.64/26 (64-127), and 172.16.10.128/26 (128-191).

Determining exact subnet ranges identifies which addresses belong to the same local broadcast domain.

Map the configured server IP address to its corresponding subnet range.

The server IP 172.16.10.66 falls into the 172.16.10.64/26 subnet (usable range 172.16.10.65 to 172.16.10.126).

Confirms the host's actual local subnet.

Compare host IP subnet to default gateway IP subnet.

The gateway IP 172.16.10.129 resides in the 172.16.10.128/26 subnet (usable range 172.16.10.129 to 172.16.10.190).

Because the host and gateway are on separate subnets, the host cannot resolve the gateway's MAC address via local ARP requests, resulting in host unreachability.

Anahtar Kavram

Default Gateway Subnet Alignment and CIDR Boundary Troubleshooting

Tahmini Süre:1m 30s

Soru 1967Soru →

A network administrator connects two enterprise switches via a fiber trunk link on interface GigabitEthernet 0/1. Shortly after enabling the link, console logs on both switches begin displaying periodic warning messages indicating a native VLAN mismatch. Interface status shows the trunk link is active, but untagged management traffic sent from VLAN 10 on Switch-A is being improperly received on VLAN 20 by Switch-B. Which of the following configuration changes will resolve this issue while restoring proper 802.1Q trunking functionality?

Reconfigure the trunk link so that both switch interfaces are configured with matching native VLAN IDs.

Lower the Spanning Tree Protocol (STP) bridge priority on Switch-A to force it to become the root bridge for VLAN 10 and VLAN 20.

Deploy a Layer 3 router subinterface to route untagged frames between VLAN 10 and VLAN 20 across the trunk.

Set both switch interfaces on the trunk link to manual full-duplex mode instead of auto-negotiation.

Cevabı ve açıklamayı göster

Cevap: Reconfigure the trunk link so that both switch interfaces are configured with matching native VLAN IDs.

Cevap

Reconfigure the trunk link so that both switch interfaces are configured with matching native VLAN IDs.

On an 802.1Q trunk link, frames belonging to the native VLAN are sent without an 802.1Q VLAN tag. When the switches on opposite ends of the trunk have mismatched native VLAN configurations, untagged frames egressing one switch's native VLAN are ingested into the receiving switch's native VLAN, causing cross-VLAN traffic leakage and generating CDP/syslog mismatch warnings. Reconfiguring both switch interfaces to use the exact same native VLAN ID resolves the mismatch and restores proper frame processing.

Adım Adım Çözüm

Analyze the log messages and symptoms reported on the switch interfaces.

Identified an 802.1Q native VLAN mismatch where Switch-A considers VLAN 10 native while Switch-B considers VLAN 20 native.

802.1Q trunking sends frames on the native VLAN without adding an explicit 802.1Q VLAN tag.

Determine the impact of untagged frame processing across a mismatched native VLAN link.

Untagged frames sent from Switch-A's native VLAN (VLAN 10) are received untagged by Switch-B and incorrectly placed into Switch-B's native VLAN (VLAN 20), causing cross-VLAN traffic leaking and log warnings.

Receiving switchports assume any untagged frame belongs to their locally configured native VLAN.

Identify the required remediation step.

Configure matching native VLAN IDs (e.g., switchport trunk native vlan 10 on both switches) to align Layer 2 VLAN tagging expectations.

Matching native VLAN configurations ensure untagged frames map to the same broadcast domain on both ends of the trunk link.

Anahtar Kavram

802.1Q Native VLAN Trunk Misconfiguration Troubleshooting

Soru 1968Soru →

A network administrator is deploying multiple access points (APs) in a high-density conference hall to support hundreds of concurrent wireless clients. During post-installation testing, users experience intermittent connectivity and severe performance degradation due to high co-channel interference (CCI). Which configuration change should the administrator make to reduce co-channel interference while maintaining continuous coverage?

Increase the transmit power on all access points to maximum levels so client devices can maintain a stronger RSSI throughout the hall.

Reduce access point transmit power levels and assign distinct non-overlapping channels to adjacent access points.

Configure adjacent access points in the 2.4 GHz band to use channels 1, 3, 5, and 7 to evenly distribute signal bandwidth.

Enable 160 MHz channel bonding on all 5 GHz access points to increase available throughput across the hall.

Cevabı ve açıklamayı göster

Cevap: Reduce access point transmit power levels and assign distinct non-overlapping channels to adjacent access points.

Cevap

Reduce access point transmit power levels and assign distinct non-overlapping channels to adjacent access points.

Reducing access point transmit power shrinks individual RF cell sizes (micro-cell deployment), allowing dense placement of access points without excessive coverage overlap. Combining reduced power with a channel plan that assigns non-overlapping channels to neighboring APs eliminates co-channel contention while supporting high client density.

Adım Adım Çözüm

Identify the cause of performance degradation in a high-density deployment.

High co-channel interference (CCI) occurs when multiple access points operating on the same frequency channel can hear each other's transmissions.

When access points share a channel and overlap in coverage, clients and APs must wait for the shared medium to become free before transmitting.

Determine the optimal radio frequency tuning method for high AP density.

Decreasing AP transmit power shrinks cell boundaries, while assigning distinct non-overlapping channels eliminates frequency contention between adjacent cells.

Creating smaller micro-cells allows more APs to be placed in a physical area without their coverage areas bleeding into adjacent APs running on the same channel.

Anahtar Kavram

Wireless Cell Sizing and Co-Channel Interference Mitigation

Tahmini Süre:1m 15s

Soru 1969Soru →

Match each switch status indicator or log message on the left with its corresponding underlying root cause on the right.

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Cevabı ve açıklamayı göster

Cevap

Each switch indicator matches its root cause: Native VLAN mismatch log matches untagged frame default VLAN mismatch; CRC errors and late collisions match duplex misconfiguration; Err-disabled port from priority 0 BPDU matches STP Root Guard enforcement; Trunk passing VLAN 10 but dropping VLAN 30 matches trunk allowed VLAN list exclusion.

Each indicator corresponds to a classic Layer 2 troubleshooting symptom: CDP log warnings indicate non-matching native VLAN IDs on 802.1Q trunks; late collisions with CRC errors indicate a full-duplex/half-duplex mismatch; an err-disabled state after receiving a priority 0 BPDU indicates STP Root Guard action; and selective VLAN dropping on an active trunk indicates an incomplete allowed VLAN list.

Adım Adım Çözüm

Analyze the CDP error message indicating native VLAN mismatch.

Identified that native VLAN settings differ between trunk endpoints (VLAN 10 vs VLAN 20).

802.1Q trunking requires identical native VLAN IDs on both ends to ensure untagged traffic is processed consistently.

Analyze interface statistics showing late collisions and CRC errors.

Identified duplex mismatch as the root cause.

Late collisions occur when a full-duplex interface transmits while a half-duplex interface on the same segment attempts to transmit after its 512-bit collision window.

Evaluate the interface transitioning to err-disabled upon receiving a priority 0 BPDU.

Identified Root Guard protection mechanism as the root cause.

Root Guard protects the root bridge topology by blocking ports that receive superior BPDUs.

Evaluate selective VLAN traffic dropping on an active trunk link.

Identified trunk allowed VLAN list pruning or exclusion.

Trunk ports forward only VLANs explicitly allowed in their configuration; missing VLANs are silently dropped.

Anahtar Kavram

Switching and VLAN Troubleshooting Indicators

Soru 1970Soru →

A network administrator installs a new 10Gbps LC duplex fiber patch cable between two core switches using matching SFP+ transceivers. After plugging in the cable, the link status LEDs on both switch interfaces remain completely dark. Testing with a visual fault locator (VFL) confirms light is passing through both fiber strands with no physical breaks. Which of the following is the most appropriate troubleshooting action to resolve this issue?

Reverse the positions of the transmit (Tx) and receive (Rx) fiber strands on one end of the LC duplex connector.

Use a copper Time-Domain Reflectometer (TDR) to locate signal attenuation points along the cable length.

Re-terminate both ends of the fiber patch cable using the T568B color-code wiring standard.

Connect a tone generator and inductive probe kit to trace light emissions along the optical cable.

Cevabı ve açıklamayı göster

Cevap: Reverse the positions of the transmit (Tx) and receive (Rx) fiber strands on one end of the LC duplex connector.

Cevap

Reverse the positions of the transmit (Tx) and receive (Rx) fiber strands on one end of the LC duplex connector.

Swapping the transmit (Tx) and receive (Rx) strands on one connector end resolves a fiber polarity inversion. Duplex fiber communications require a crossover layout (Tx to Rx). When connected straight-through (Tx-to-Tx / Rx-to-Rx), optical signals are directed into transmit lasers rather than receivers, preventing link establishment even when light continuity is verified.

Adım Adım Çözüm

Analyze the diagnostic test results

The visual fault locator (VFL) verifies continuity and absence of physical glass breaks in both strands.

Eliminates physical cable damage or excessive bend loss as the root cause.

Identify duplex fiber transmission requirements

Duplex fiber links require transmit (Tx) at Node 1 to align with receive (Rx) at Node 2, and vice versa.

If Tx connects to Tx and Rx connects to Rx (straight-through polarity mismatch), neither optical transceiver receives incoming light.

Apply the corrective physical cable adjustment

Unclip and swap the Tx and Rx connectors at one end of the LC duplex fiber patch cable.

Establishes proper fiber polarity crossover, allowing optics to establish a link.

Anahtar Kavram

Fiber Optic Polarity and Duplex Connection Troubleshooting

Tahmini Süre:1m 30s

Soru 1971Soru →

A network technician is conducting diagnostic tests on a newly deployed workstation. Match each command-line utility command to its correct network troubleshooting function or operational output.

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Cevabı ve açıklamayı göster

Cevap

netstat -an corresponds to displaying active TCP/UDP listening ports and numerical connections; dig -x corresponds to performing a reverse DNS lookup; pathping corresponds to measuring per-hop latency and packet loss over time; arp -a corresponds to displaying local IP-to-MAC address mappings.

Each command-line utility targets a specific diagnostic domain: netstat -an reports transport-layer listening ports and sockets numerically; dig -x performs reverse DNS PTR lookups; pathping assesses sustained hop-by-hop latency and packet loss; arp -a outputs local Layer 2 to Layer 3 address resolution entries.

Adım Adım Çözüm

Analyze the primary function of protocol/session display tools.

Identify that netstat displaying socket statuses numerically matches listing listening ports and established TCP/UDP sockets.

The -n flag prevents hostname resolution, speeding up output and showing exact port numbers.

Evaluate the specialized DNS query flags.

Identify dig -x as the reverse DNS lookup invocation.

The -x flag automatically formats the target IP address into an in-addr.arpa or ip6.arpa PTR query.

Differentiate path diagnostic utilities.

Identify pathping as the tool combining traceroute with sustained ping stats.

Pathping monitors intermediate hops over several minutes to calculate exact packet loss percentages per hop.

Examine local address resolution tools.

Identify arp -a as the command for displaying the Address Resolution Protocol cache.

ARP links Layer 2 physical addresses to Layer 3 IP addresses for the local broadcast domain.

Anahtar Kavram

Command-Line Network Utilities & Operational Diagnostics

Soru 1972Soru →

A network administrator is troubleshooting network connectivity issues for automated guided vehicles (AGVs) deployed on a newly provisioned warehouse floor subnet (VLAN 45: $10.45.0.0/23$ ). The AGVs cannot communicate with the central controller on another subnet. Inspecting the IP configuration on an AGV displays the following terminal output:

IPv4 Address. . . . . . . . . . . : 169.254.12.88
Subnet Mask . . . . . . . . . . . : 255.255.0.0
Default Gateway . . . . . . . . . :

The central DHCP server is located on VLAN 10 ( $10.10.0.50$ ) with a valid, unexhausted scope for VLAN 45. Which TWO of the following statements correctly identify the underlying cause and the required resolution?

Geçerli olan tümünü seçin

The host automatically generated an Automatic Private IP Addressing (APIPA) address because DHCP broadcast requests are not reaching the central DHCP server.

An IP helper address (DHCP relay) must be configured on the VLAN 45 default gateway router interface pointing to the DHCP server at 10.10.0.50.

The host cannot reach external subnets because the default gateway was not manually specified as 169.254.0.1 on the client network adapter.

The DHCP server scope allocation failed because a /23 prefix length only provides a maximum of 254 usable host IP addresses.

Cevabı ve açıklamayı göster

Cevap: The host automatically generated an Automatic Private IP Addressing (APIPA) address because DHCP broadcast requests are not reaching the central DHCP server.; An IP helper address (DHCP relay) must be configured on the VLAN 45 default gateway router interface pointing to the DHCP server at 10.10.0.50.

Cevap

The host automatically generated an APIPA address because DHCP broadcast requests were blocked across subnets, and an IP helper address (DHCP relay) must be configured on the VLAN 45 gateway router interface pointing to 10.10.0.50.

The presence of a 169.254.x.x address confirms that the client failed to receive a DHCP lease and assigned itself an Automatic Private IP Address (APIPA). Because the central DHCP server is situated on a different subnet (VLAN 10) than the client (VLAN 45), Layer 2 DHCP Discover broadcasts are blocked by default at the router interface. Configuring an IP helper address (DHCP relay) on the VLAN 45 router interface allows the router to relay client requests as unicast packets directly to the central DHCP server.

Adım Adım Çözüm

Analyze the client IP configuration snippet.

The IP address 169.254.12.88 belongs to the link-local Automatic Private IP Addressing (APIPA) block.

Operating systems automatically assign an APIPA address when dynamic configuration via DHCP times out or fails.

Identify why DHCP communications are failing across subnets.

DHCP Discover packets are sent as Layer 2 broadcasts, which routers do not forward across VLAN boundaries.

The client resides on VLAN 45 while the central DHCP server is located on VLAN 10.

Determine the necessary corrective action.

Configure an IP helper address (DHCP relay) on the VLAN 45 router interface pointing to 10.10.0.50.

A DHCP relay agent captures local DHCP broadcast traffic, encapsulates it as unicast IP packets, and forwards it to the designated DHCP server.

Anahtar Kavram

Troubleshooting APIPA Assignment and Cross-Subnet DHCP Relay (IP Helper)

Tahmini Süre:1m 30s

Soru 1973Soru →

A network management server suffers a catastrophic storage failure on Thursday morning. The enterprise backup policy specifies a full backup performed every Sunday at 00:00 and incremental backups performed daily from Monday through Wednesday at 23:00. Arrange the following steps in the correct sequential order required to fully restore the system to its most recent state prior to the failure.

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Cevap

The correct sequence begins with preparing the replacement storage media, followed by restoring the Sunday full backup baseline, and subsequently restoring each daily incremental backup in strict chronological order: Monday, Tuesday, and Wednesday.

Restoring from an incremental backup scheme requires initializing target hardware, restoring the base full backup, and then applying every incremental backup taken since the full backup in chronological order. Because each incremental backup relies on all preceding backups since the last full backup, omitting or misordering any step prevents full recovery.

Adım Adım Çözüm

Prepare target storage media

Replacement storage volume formatted and ready

Target disk volumes must be initialized and mounted before file system restoration can begin.

Restore Sunday full backup

Baseline system image restored to Sunday 00:00 state

The full backup contains the foundational operating system, configuration, and data baseline.

Apply daily incremental backups sequentially (Monday -> Tuesday -> Wednesday)

System fully restored to Wednesday 23:00 state

Incremental backups record only data changed since the previous backup job. Restoring them requires applying every daily delta file in exact chronological sequence.

Anahtar Kavram

Incremental Backup Restoration Process

Tahmini Süre:1m 30s

Soru 1974Soru →

An infrastructure team is auditing an 802.1Q trunk connection between Switch-1 and Switch-2 on interface FastEthernet 0/24. Syslog on Switch-1 displays `%CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on FastEthernet0/24 (1), with Switch-2 FastEthernet0/24 (30)`. Additionally, hosts assigned to VLAN 30 on Switch-1 cannot reach resources on VLAN 30 attached to Switch-2. A check of Switch-1 interface FastEthernet 0/24 shows that its trunk allowed VLAN list currently includes only VLANs 10 and 20. Which TWO of the following configuration steps must be performed on Switch-1 to resolve the native VLAN warning and allow VLAN 30 traffic to traverse the link? (Select TWO.)

Geçerli olan tümünü seçin

Reconfigure the native VLAN on interface FastEthernet 0/24 of Switch-1 to VLAN 30.

Add VLAN 30 to the list of allowed VLANs on interface FastEthernet 0/24 of Switch-1.

Set the Spanning Tree Protocol priority for VLAN 30 on Switch-1 to the maximum value of 65535.

Set interface FastEthernet 0/24 on Switch-1 to half-duplex mode to allow untagged frames.

Cevabı ve açıklamayı göster

Cevap: Reconfigure the native VLAN on interface FastEthernet 0/24 of Switch-1 to VLAN 30.; Add VLAN 30 to the list of allowed VLANs on interface FastEthernet 0/24 of Switch-1.

Cevap

The technician must reconfigure the native VLAN on Switch-1 FastEthernet 0/24 to VLAN 30 and append VLAN 30 to the trunk's allowed VLAN list.

Resolving this issue requires fixing two distinct misconfigurations on Switch-1's trunk port. First, changing the native VLAN to VLAN 30 eliminates the mismatch flagged by CDP. Second, adding VLAN 30 to the trunk's allowed VLAN list enables tagged frames for VLAN 30 to pass between the two switches.

Adım Adım Çözüm

Analyze the CDP error log for the native VLAN configuration difference.

Switch-1 uses native VLAN 1, while Switch-2 uses native VLAN 30 on interface FastEthernet 0/24.

Matching native VLAN configurations across both ends of an 802.1Q trunk link is required to prevent CDP error logs and untagged traffic leaks.

Inspect the allowed VLAN trunk pruning list on Switch-1.

VLAN 30 is absent from Switch-1's allowed list (which only lists VLANs 10 and 20).

Trunk interfaces drop traffic for any VLAN not explicitly included in their allowed VLAN filter.

Formulate the required remediation commands for Switch-1 interface FastEthernet 0/24.

Reconfigure the native VLAN to 30 and append VLAN 30 to the allowed list.

Executing both changes resolves the native VLAN mismatch alert and permits VLAN 30 traffic across the trunk link.

Anahtar Kavram

802.1Q Trunking Native VLAN Matching and Allowed VLAN List Configuration

Soru 1975Soru →

A network technician needs to pinpoint the precise location of a conductor break in a 90-meter Category 6 UTP cable run hidden behind drywall. A basic wire mapper confirms an open circuit on pin 3, but cannot determine how far along the cable the fault occurred. Which diagnostic tool should the technician use to measure the exact distance to the cable break?

Time-Domain Reflectometer (TDR)

Tone generator and probe trace kit

Optical Power Meter (OPM)

Protocol analyzer

Cevabı ve açıklamayı göster

Cevap: Time-Domain Reflectometer (TDR)

Cevap

Time-Domain Reflectometer (TDR)

A Time-Domain Reflectometer (TDR) is specifically designed to send electrical pulses through copper media and analyze the reflected signals. By calculating the time delay of the reflection against the cable's velocity of propagation, a TDR precisely measures the distance to physical cable breaks, kinks, or impedance mismatches.

Adım Adım Çözüm

Identify the physical layer fault and diagnostic goal

The goal is to determine the exact distance along a copper cable run where a conductor break (open circuit) is located.

Basic wire mappers only confirm electrical continuity across pins but lack signal reflection measurement capabilities.

Select the appropriate diagnostic tool designed for copper cable fault location

Select a Time-Domain Reflectometer (TDR).

A TDR transmits a signal pulse along copper conductors and measures the elapsed time for reflections caused by impedance changes (such as an open circuit or short) to return, calculating distance based on nominal velocity of propagation.

Anahtar Kavram

Pinpointing Copper Cable Fault Locations with a TDR

Tahmini Süre:1m 0s

Soru 1976Soru →

A network administrator configures a new DHCP scope on a centralized server to service clients on VLAN 20 (subnet $10.20.10.0/24$ ). Users on VLAN 20 report that they can successfully communicate with other local hosts on VLAN 20, but cannot access external networks or corporate servers located on other subnets. Running `ipconfig /all` on an affected client displays an IPv4 address of $10.20.10.45$ with a subnet mask of $255.255.255.0$ , but the Default Gateway field is empty. Which of the following is the most likely cause of this issue?

DHCP Option 003 (Router) was not configured within the DHCP scope settings.

The router interface serving VLAN 20 is missing an IP helper address configuration.

The client host failed to contact the DHCP server and auto-generated an APIPA address.

The IP address

10.20.10.45

is reserved as the broadcast address for the

10.20.10.0/24

subnet.

Cevabı ve açıklamayı göster

Cevap: DHCP Option 003 (Router) was not configured within the DHCP scope settings.

Cevap

DHCP Option 003 (Router) was not configured within the DHCP scope settings.

DHCP clients require specific options to configure network settings beyond basic IP address assignment. DHCP Option 003 delivers the default gateway IP address to clients. When Option 003 is omitted from a scope configuration, clients receive valid IP addresses and subnet masks allowing local Layer 2 traffic, but lack the default gateway setting required to route packets to external subnets.

Adım Adım Çözüm

Analyze the IP configuration returned by the diagnostic command.

The client has acquired

10.20.10.45/24

, which is a valid lease from the configured

10.20.10.0/24

pool.

Successful lease acquisition confirms physical layer 2 connectivity and functioning Layer 3 DHCP relay mechanisms.

Evaluate the symptom of intra-subnet versus inter-subnet communication.

Hosts can communicate within VLAN 20 but fail to reach external destinations.

Intra-subnet communication uses Layer 2 MAC addresses via ARP. Inter-subnet communication requires routing through a default gateway.

Correlate the missing Default Gateway field with DHCP server parameters.

DHCP Option 003 supplies the Default Gateway parameter to clients during the lease handshake.

Omitting Option 003 causes clients to successfully receive IP addresses and subnet masks while lacking the default route necessary to forward traffic outside the local network.

Anahtar Kavram

DHCP Option Configuration and Scope Parameters

Soru 1977Soru →

A network administrator is configuring three neighboring access points installed along a corridor in an enterprise building. The access points operate on standard 20 MHz channel widths within the 2.4 GHz spectrum. Which of the following channel assignment combinations will ensure contiguous wireless coverage while completely preventing adjacent-channel interference?

Channels 1, 6, and 11

Channels 1, 5, and 9

Channels 2, 7, and 12

Channels 3, 6, and 9

Cevabı ve açıklamayı göster

Cevap: Channels 1, 6, and 11

Cevap

Channels 1, 6, and 11 represent the three primary non-overlapping 20 MHz channels available in the 2.4 GHz spectrum.

In the 2.4 GHz band, channels are spaced 5 MHz apart. Standard 20 MHz transmissions require a minimum separation of 5 channel numbers (25 MHz between center frequencies) to prevent frequency skirts from overlapping. Channels 1, 6, and 11 represent the standard set of non-overlapping channels in North America and international deployments.

Adım Adım Çözüm

Analyze the channel spacing and bandwidth structure of the 2.4 GHz ISM band.

Each channel number represents a 5 MHz shift in center frequency, while a standard channel mask spans 20 to 22 MHz.

Because center frequencies are separated by only 5 MHz, adjacent channel numbers overlap heavily.

Calculate the minimum separation needed between channel center frequencies to avoid overlap.

A minimum separation of 25 MHz (5 channel numbers) is necessary to keep signal skirts isolated.

Sufficient frequency separation prevents adjacent-channel interference, which impairs frame preamble detection and causes packet corruption.

Identify the standard non-overlapping channel plan for three adjacent coverage cells.

Assigning channels 1 (2412 MHz), 6 (2437 MHz), and 11 (2462 MHz) provides 25 MHz separation between all adjacent access points.

This allocation maintains maximum cell density without generating inter-cell interference.

Anahtar Kavram

2.4 GHz Non-Overlapping Channel Planning

Soru 1978Soru →

A network administrator is designing a backup strategy for a critical syslog telemetry database. The operational goal is to shorten the nightly backup execution window while ensuring that restoring the system after a catastrophic failure requires applying the weekly full backup and at most one subsequent backup file. Which backup strategy should the administrator implement to meet these requirements?

Perform a weekly full backup on Sunday and daily differential backups on weeknights.

Perform a weekly full backup on Sunday and daily incremental backups on weeknights.

Perform daily full backups every weeknight.

Perform daily synthetic differential backups without an initial full backup baseline.

Cevabı ve açıklamayı göster

Cevap: Perform a weekly full backup on Sunday and daily differential backups on weeknights.

Cevap

Performing a weekly full backup combined with daily differential backups shortens the daily backup window compared to full backups and ensures a recovery process requiring only the full baseline and the latest differential file.

Differential backups capture all changes made since the last full backup baseline. Because the archive bit is not cleared, each differential file contains cumulative changes. Restoring system data requires only two items: the baseline full backup and the latest differential backup file. This minimizes nightly backup windows compared to daily full backups while keeping recovery overhead minimal.

Adım Adım Çözüm

Analyze the requirement for daily backup window duration.

Full daily backups are eliminated because they take the longest time to execute every night.

The scenario specifically requests minimizing the nightly backup execution window.

Analyze the recovery constraint requiring at most one additional backup file after the baseline.

Incremental backups are eliminated because restoring requires the full baseline plus all sequential incremental files created up to the failure point.

Incremental backups record changes since the last incremental backup, accumulating multiple files across the week.

Evaluate the differential backup model against both constraints.

Differential backups copy all changes since the last full backup without resetting the archive bit. Thus, restore operations only require the initial full backup baseline and the single most recent differential backup file.

Differential backups satisfy both the reduced backup window requirement and the single-file restore addition rule.

Anahtar Kavram

Differential vs Incremental Backup Restoration Characteristics

Soru 1979Soru →

A network engineer is troubleshooting a newly installed multi-strand MPO/MTP multimode fiber trunk cable connected between two high-density distribution switches. Although transceivers are installed and powered, the link status remains down, and switch logs indicate insufficient optical power reception. Which of the following diagnostic steps or corrective actions should the engineer take to resolve this physical layer issue? (Select TWO.)

Geçerli olan tümünü seçin

Inspect the fiber ferrule endfaces with an optical inspection scope and clean contaminated connectors using specialized lint-free tools.

Measure the optical power loss across the fiber strands with an optical power meter and light source to verify correct polarity and signal strength.

Use a metallic Time-Domain Reflectometer (TDR) to measure resistance variations and locate split pairs within the optical strands.

Attach a tone generator and inductive probe to trace electrical signals along the fiber jacket through the cable trays.

Cevabı ve açıklamayı göster

Cevap: Inspect the fiber ferrule endfaces with an optical inspection scope and clean contaminated connectors using specialized lint-free tools.; Measure the optical power loss across the fiber strands with an optical power meter and light source to verify correct polarity and signal strength.

Cevap

The correct troubleshooting actions are inspecting and cleaning the fiber ferrule endfaces with an optical inspection scope, and measuring optical loss and polarity using an optical power meter paired with a light source.

Inspecting ferrule endfaces with a fiber inspection scope reveals microscopic debris causing signal insertion loss, and using an optical power meter with a light source quantifies decibel loss and confirms optical polarity across multi-fiber connectors.

Adım Adım Çözüm

Identify the transmission media and symptom.

The media is multi-strand multimode fiber cabling (MPO/MTP) exhibiting optical attenuation and link down status.

Choosing diagnostic tools requires matching tool capabilities with optical fiber physical properties.

Select appropriate fiber optic diagnostic tools.

Optical inspection scopes identify physical contamination on ferrules, while an optical power meter (OPM) measures signal attenuation and confirms correct transmit/receive polarity.

Fiber optic troubleshooting relies on light transmission metrics and physical endface cleanliness rather than electrical conductivity testing.

Eliminate inappropriate copper testing tools.

Discard tone generators and copper TDRs.

Copper testing tools rely on electrical signals and metallic continuity, which cannot operate on optical glass fibers.

Anahtar Kavram

Fiber Optic Physical Layer Troubleshooting & Tool Selection

Soru 1980Soru →

A network administrator is troubleshooting severe performance degradation on an enterprise network segment. Users report extreme file transfer delays when communicating with a local server connected to interface GigabitEthernet 0/5 on Switch-SW1. Interface metrics on Switch-SW1 reveal a rising count of late collisions, frame check sequence (FCS) errors, and alignment errors, despite low overall bandwidth utilization. Further inspection shows the server's network adapter is manually configured for 1000 Mbps Full-Duplex, whereas the connected switch port is set to auto-negotiation. Which of the following accounts for the root cause of this issue?

Physical cable damage or electromagnetic interference along the run is causing signal attenuation and frame corruption.

The switch port auto-negotiation failed to detect full-duplex mode, defaulting to half-duplex and creating a duplex mismatch.

The switch interface and server interface are configured with mismatched native VLANs, causing untagged frame drops.

Spanning Tree Protocol has assigned a high numerical priority to Switch-SW1, placing interface GigabitEthernet 0/5 into an STP blocking state.

Cevabı ve açıklamayı göster

Cevap: The switch port auto-negotiation failed to detect full-duplex mode, defaulting to half-duplex and creating a duplex mismatch.

Cevap

The switch port auto-negotiation failed to detect full-duplex mode, defaulting to half-duplex and creating a duplex mismatch.

When an Ethernet port configured for auto-negotiation is connected to a port with manually hardcoded speed and duplex, IEEE 802.3 standards specify that the auto-negotiating port can detect speed through parallel detection but cannot negotiate duplex. Consequently, the auto-negotiating switch port defaults to half-duplex mode. Because the connected server operates in full-duplex mode, it transmits data without checking for carrier sense. The switch port, operating in half-duplex, perceives these simultaneous transmissions as collisions. When collisions occur after the collision window (64 bytes), they are logged as late collisions and cause FCS/CRC errors, resulting in extreme performance degradation.

Adım Adım Çözüm

Analyze the reported interface statistics and symptoms.

Identified late collisions, FCS errors, and alignment errors alongside slow transfer rates.

Late collisions occur when a device operating in half-duplex detects a collision after transmitting the first 64 bytes of a frame.

Evaluate the interface speed and duplex configuration settings on both connected ends.

Determined that the server adapter is hardcoded to full-duplex while the switch port is set to auto-negotiation.

Ethernet auto-negotiation standards dictate that if link partner parameters cannot be negotiated, speed can be detected via parallel detection, but duplex defaults to half-duplex.

Synthesize the configuration mismatch with the observed symptoms.

The server transmits continuously in full-duplex mode, while the switch port expects half-duplex CSMA/CD operation, causing the switch to detect collisions during server transmission.

This operational mismatch directly generates late collisions, FCS errors, and severe packet retransmissions.

Anahtar Kavram

Duplex auto-negotiation behavior and symptom identification in Ethernet switching

ÖncekiSayfa 99 / 112Sonraki

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