All practice questions

A network operations center team notices periodic bandwidth spikes on a branch office WAN router interface. While SNMP counter polling indicates overall interface throughput, it fails to reveal which internal endpoints or protocols are responsible for the spikes. Which network performance telemetry technology should be implemented on the router interface to capture per-flow traffic details, including source and destination IP addresses?

A network administrator is troubleshooting an issue where a client workstation is resolving an outdated IP address for a local server. Arrange the standard operating system name resolution steps in order from FIRST evaluated source to LAST evaluated source during a hostname lookup request.

During a network audit, a technician discovers that Switch-1 has its trunk interface native VLAN set to VLAN 10, while Switch-2 on the opposite end of the trunk link has its native VLAN set to VLAN 20. Which of the following issues will occur as a direct result of this misconfiguration?

A network administrator installs a new single-mode fiber-optic cable run between two network switches in adjacent buildings. Which tool should the administrator use to measure signal attenuation and pinpoint light loss along the fiber link?

A network engineer configures an extended Access Control List (ACL) on an enterprise edge router to allow internal workstations on the subnet $10.100.4.0/24$ to perform domain name queries against an external DNS server at IP address $8.8.8.8$. The engineer enters the following rule on the outbound interface:

`permit udp 10.100.4.0 0.0.0.255 host 8.8.8.8 eq 53`

Users report that basic DNS lookups succeed, but certain applications fail when DNS response payloads exceed $512$ bytes or when performing DNSSEC lookups that require switching transport protocols. Which modification to the ACL configuration will resolve this issue while adhering to the principle of least privilege?

A network technician is troubleshooting an intermittent Gigabit Ethernet connection over a 70-meter Category 6 UTP cabling run between a core switch and a high-density wireless access point. Although a basic continuity wiremapper shows all eight conductors properly connected pin-to-pin, the link frequently drops or negotiates down to 100 Mbps under high traffic loads. Which of the following diagnostic steps or corrective actions should the technician take to identify and resolve this issue? (Select TWO.)

A network technician needs to verify basic ICMP IP reachability and trace the hop-by-hop route from a Windows workstation to a remote server at 10.0.4.15. Which of the following command-line utilities should the technician use? (Select TWO.)

A network engineer is troubleshooting high optical attenuation along a 1,500-meter single-mode fiber-optic link between two data center facilities. While an optical power meter confirms that overall signal strength drops below acceptable thresholds, it cannot identify where along the cable run the issue exists. Which hardware tool should the engineer use to pinpoint the exact distance to the microbend or splice failure causing the signal loss?

A user connects a laptop to a wired network jack in a remote conference room but cannot access any internal or external network resources. A technician executes `ipconfig /all` on the workstation and receives the following output:

IPv4 Address. . . . . . . . . . . : 169.254.22.81
Subnet Mask . . . . . . . . . . . : 255.255.0.0
Default Gateway . . . . . . . . . :

Which of the following is the most likely cause of this issue?

A network technician is troubleshooting connectivity failures on a newly provisioned branch office subnet, VLAN 70 ($10.70.0.0/23$). Client workstations connected to VLAN 70 fail to access corporate resources and receive autoconfigured IP addresses in the range $169.254.18.1$ to $169.254.18.254$ with a subnet mask of $255.255.0.0$. The centralized DHCP server resides on VLAN 10 ($10.10.0.50$). Inspection of the Layer 3 switch reveals that Interface VLAN 70 is configured with IP address $10.70.0.1/23$, but no IP helper address is configured, and logging on the DHCP server indicates that the IP pool for $10.70.0.0/23$ has reached $100\%$ capacity.

Which of the following factors explain why client devices are assigned $169.254.x.x$ addresses and detail the required remediation steps? (Select TWO.)

Match each network troubleshooting task to the most appropriate hardware tester or protocol analysis tool.

A network technician is investigating a situation where users at a remote branch office cannot reach external websites following a WAN router update. The technician gathered information and established a theory that an access control list (ACL) on the edge router was inadvertently blocking outbound DNS traffic on UDP port 53. The technician then applied a temporary test rule and performed a lookup, confirming that the ACL was indeed the root cause of the failure. According to the CompTIA troubleshooting methodology, which of the following actions should the technician perform NEXT?

A network administrator is troubleshooting an intermittent reachability issue affecting a Linux web server located in a corporate DMZ subnet ($10.50.100.0/24$). Internal workstations on the LAN ($192.168.10.0/24$) can ping their local default gateway ($192.168.10.1$), but cannot reach the web server at $10.50.100.45$ on TCP port 443. The administrator executes diagnostic commands and observes the following output:

text C:\Users\admin> traceroute 10.50.100.45 traceroute to 10.50.100.45, 30 hops max, 60 byte packets 1 192.168.10.1 (192.168.10.1) 1.102 ms 0.985 ms 0.950 ms 2 10.200.1.1 (10.200.1.1) 3.421 ms 3.211 ms 3.105 ms 3 * * * 4 * * *

A inspect of the gateway router ($10.200.1.1$) inbound Access Control List (ACL) on the interface facing the core router reveals:

text 10 permit tcp 192.168.10.0 0.0.0.255 10.50.100.0 0.0.0.255 eq 80 20 permit icmp 192.168.10.0 0.0.0.255 10.50.100.0 0.0.0.255 30 deny ip any any

Additionally, direct diagnostic checks on the web server ($10.50.100.45$) show its IPv4 address is configured as $10.50.100.45/24$ with a default gateway configured as $10.50.101.1$.

Which TWO of the following underlying issues are preventing workstation connections to the web server over HTTPS?

Users in an office building report frequent dropouts and poor throughput on the 2.4 GHz wireless network. A network administrator conducts a frequency audit and discovers that neighboring access points are assigned to non-overlapping channels 1, 6, and 11. However, the internal access point experiencing issues is configured to use Channel 3 with a 40 MHz channel bonding width. Which of the following identifies the primary root cause of the wireless performance degradation?

A network administrator is implementing a telemetry and metric collection framework across core edge routers. The management policy mandates cryptographic authentication and payload encryption for device health polling, alongside flow-level traffic analysis to identify bandwidth-intensive applications. Which of the following solutions should the administrator deploy to fulfill these monitoring objectives? (Select TWO.)

A network technician is hardening an access switch installed in a publicly accessible building lobby. A vulnerability audit indicates that the switch port connected to the lobby Ethernet jack is transmitting detailed hardware specifications, system capabilities, and native device hostnames to connected client devices. Which of the following configuration changes should the technician implement on this interface to resolve the information disclosure vulnerability?

A network administrator loses all network access to a remote branch router following a fiber cut on the primary WAN circuit. The administrator needs to establish a command-line interface (CLI) session to inspect the router's boot process and interface status without relying on the down IP network link. Which mechanism provides remote management capabilities in this out-of-band scenario?

A network administrator observing traffic on a managed switch detects unauthorized Ethernet frames originating from a host on VLAN 10 arriving at a server isolated on VLAN 20 without passing through an intervening router. Packet analysis shows that the frames contain two 802.1Q headers: an outer tag corresponding to VLAN 10 (the native VLAN of the trunk link) and an inner tag specifying VLAN 20. Which of the following attack types is being executed?

A network technician installs new Category 6 UTP cable runs in a renovated office space. After terminating the cables, the technician uses a basic pin-to-pin continuity tester, which confirms that all eight conductors are correctly wired 1-to-1 at both ends. However, when workstations are connected, network performance is severely degraded by high rates of Near-End Crosstalk (NEXT) and frame errors. Which diagnostic tool should the technician use to identify the split-pair anomaly causing this signal degradation?

A network technician is performing physical layer and wireless infrastructure testing across a corporate facility. Match each diagnostic troubleshooting scenario to the most appropriate hardware testing tool required to resolve the issue.