All practice questions

A network administrator receives reports that newly arriving wireless clients on a high-density office VLAN ($192.168.32.0/23$) are unable to access network resources. Inspecting an affected workstation via `ipconfig /all` reveals the following output:

text
IPv4 Address. . . . . . . . . . . : 169.254.112.45
Subnet Mask . . . . . . . . . . . : 255.255.0.0
Default Gateway . . . . . . . . . :
DHCP Server . . . . . . . . . . . :

Wireless 802.1X authentication logs show that clients authenticate successfully, but DHCP lease requests time out. Further inspection of the centralized DHCP server shows that the scope for $192.168.32.0/23$ has $508$ active leases out of $508$ total allocated addresses, with a default lease duration of $8$ days.

Which of the following actions is the most appropriate resolution to fix the IP address assignment failure?

A network administrator is investigating an issue where corporate users cannot authenticate to the 802.1X wireless network following a server maintenance window. The administrator suspects that an expired RADIUS server SSL certificate is preventing successful EAP-TLS handshakes. To test this theory, the administrator installs a valid test certificate on a staging RADIUS server and successfully authenticates a test client. According to the CompTIA troubleshooting methodology, what is the immediate NEXT step the administrator should perform?

A network administrator has verified that a recently modified firewall access control list (ACL) blocking TCP port 636 is the root cause of directory authentication failures for hybrid cloud VPN users. The administrator confirmed this theory after testing the ACL modification in a staging environment. According to the CompTIA troubleshooting methodology, which TWO of the following actions should the administrator perform NEXT during the upcoming phase? (Select TWO.)

A network administrator is preparing a formal Request for Change (RFC) to deploy updated security policies across several branch office routers. Before presenting the request to the Change Advisory Board (CAB) for formal review, which of the following elements must be included in the RFC documentation?

A network administrator is troubleshooting an intermittent 10GBASE-LR single-mode optical fiber link between two campus buildings. Switch port diagnostics indicate high optical signal attenuation and excessive return loss (back reflection) following a recent patch panel maintenance window. Optical transceivers on both endpoints report normal transmit power levels. Which of the following actions should the network administrator perform to accurately pinpoint the fault location and resolve the physical layer degradation? (Select TWO.)

A network administrator needs to grant third-party auditors access to an internal web-based financial dashboard. The security policy dictates that remote users must not be required to install dedicated client software or agent applications on their unmanaged personal endpoints, yet all session traffic must remain encrypted over the internet. Which remote access technology best meets these requirements?

A network security administrator must configure an IPv4 Access Control List (ACL) on a router to enforce access policies for the internal host network ($10.1.1.0/24$) communicating with a database server ($172.16.10.5$). The policy requires that host $10.1.1.15$ is allowed HTTP access to the server, while all other hosts in $10.1.1.0/24$ are denied HTTP access. However, all hosts in $10.1.1.0/24$ must be allowed all other IP traffic to the server, and all remaining traffic from any other network must be dropped. Place the ACL statements in the correct top-to-bottom execution order to enforce this security policy without rule shadowing.

A user's workstation is assigned the static IP address $10.0.4.50$ with a subnet mask of $255.255.255.0$. The workstation can successfully ping other local computers on the $10.0.4.0/24$ network, but it cannot reach any servers on external subnets or the internet. An administrator reviews the network configuration and notes that the default gateway is set to $10.0.5.1$. Which of the following is the root cause of the outbound connectivity issue?

A network administrator is troubleshooting connectivity issues on a corporate wireless guest network spanning the $192.168.100.0/24$ subnet. Transient users report that their laptops periodically fail to connect to network resources and receive self-assigned IP addresses in the $169.254.0.0/16$ range during peak operating hours. Upon inspecting the central DHCP server status, the administrator observes the following command output snippet:

text
DHCP Scope: Guest_VLAN100
Subnet Prefix: 192.168.100.0/24
Range: 192.168.100.10 - 192.168.100.250
Total Scope Addresses: 241
Active Leases: 241 (100% utilized)
Pending Requests: 14 (Dropped - No available addresses)
Lease Duration: 8 days 00:00:00

Physical attendance logs confirm that no more than 60 guest users are ever present in the facility concurrently. Which of the following is the most likely root cause of this issue?

During a post-incident audit following a scheduled core network maintenance event, auditors noted that engineers spent several hours attempting to resolve unexpected packet loss on a newly updated WAN interface rather than reverting to the previous baseline configuration. Although the maintenance window eventually expired without restoring stable service, the deployment team had not breached any formal protocols because no specific metrics were defined to dictate when troubleshooting should cease and restoration must begin. Which specific element of the Request for Change (RFC) documentation was missing or improperly constructed?

A network engineer is troubleshooting a client workstation that cannot connect to an internal web portal using its hostname `srv01.corp.internal`. The engineer executes two `nslookup` queries from the client's command prompt:

text
C:\> nslookup srv01.corp.internal
Server: UnKnown
Address: 192.168.1.1
*** UnKnown can't find srv01.corp.internal: Non-existent domain

C:\> nslookup srv01.corp.internal 10.0.0.53
Server: dc01.corp.internal
Address: 10.0.0.53

Name: srv01.corp.internal
Address: 10.0.0.150

Based on the output above, which of the following are the MOST likely root causes of the name resolution issue on the workstation? (Select TWO.)

An enterprise organization is mitigating two distinct security concerns regarding its web services: unauthorized tampering of REST API transactional data in transit, and frequent web server unresponsiveness caused by TCP SYN flood attacks. Which TWO of the following security mechanisms directly address the Integrity and Availability pillars of the CIA triad to mitigate these specific issues? (Select TWO)

Match each physical layer cabling diagnostic tool to the primary troubleshooting task or measurement it is designed to perform.

An IT technician is troubleshooting name resolution issues on an administrator workstation. The technician issues an `nslookup` command for `app.finance.local` and receives a successful reply pointing to `192.168.10.50`. However, when attempting to ping `app.finance.local` from the same machine, the system attempts to send traffic to `10.0.0.99` and times out.

text
C:\Users\Admin> nslookup app.finance.local
Server: dns01.corp.internal
Address: 10.0.0.1

Name: app.finance.local
Address: 192.168.10.50

C:\Users\Admin> ping app.finance.local
Pinging app.finance.local [10.0.0.99] with 32 bytes of data:
Request timed out.

Which of the following is the most likely cause of the discrepancy in resolved IP addresses?

A network technician is performing RF site troubleshooting in a manufacturing facility to resolve persistent wireless connectivity issues. Match each observed wireless symptom or environmental phenomenon on the left with its correct physical root cause or signal behavior on the right.

A network technician is addressing severe voice quality degradation on an enterprise VoIP network following a core router firmware update. Place the technician's troubleshooting procedures in the correct sequence according to the official CompTIA troubleshooting methodology.

During an enterprise network audit, users report periodic voice distortion and video freezing during teleconference sessions over a WAN connection. Telemetry shows that overall link utilization is below 35% and total packet loss is 0%, but packet inter-arrival times fluctuate significantly between 4 ms and 130 ms. Which network performance metric is directly causing this quality degradation?

A security engineer is updating an organization's wireless baseline documentation to prepare for a migration from legacy Wi-Fi security protocols to WPA3-Enterprise across all corporate facilities. Which of the following technical features and requirements specifically apply when implementing WPA3-Enterprise? (Select TWO)

A network engineering team is preparing to modify Access Control Lists (ACLs) across core datacenter routers to restrict outdated management protocols and enforce secure logging. Before executing the modifications during the scheduled maintenance window, which TWO of the following tasks must be completed as part of the standard change management workflow? (Select TWO.)

Match each Virtual Private Network (VPN) protocol or header component to its corresponding operational characteristics and transport specifications.