N10-009 Free Practice Questions — Page 14 (2026)

Question 127

Which of the following routing technologies uses an attribute list for path selection?

A. BGP

B. RIP

C. EIGRP

D. OSPF

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Correct Answer: A

Explanation:
BGP selects routes using an ordered list of path attributes (such as AS-Path, Local Preference, MED, Origin, and Weight). The other protocols rely on single or composite metrics rather than an attribute list.

Question 128

A network engineer adds a tunnel for a new branch network. Which of the following ensures that all data is encrypted inside the tunnel?

A. ESP

B. SSH

C. GRE

D. IKE

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Correct Answer: A

Explanation:
Encapsulating Security Payload (ESP) is part of the IPsec suite and provides encryption for data carried inside a tunnel, along with integrity and authentication. GRE only encapsulates without encryption, IKE negotiates keys and security associations, and SSH secures management sessions rather than network tunnels.

Question 129

A network administrator needs to deploy a new wireless solution at a customer site. All external users must provide credentials before being granted access to the wireless solution. Which of the following would best meet the requirements of this installation?

A. Adjust the bands to be non-overlapping.

B. Set up lightweight access points.

C. Enable enterprise authentication.

D. Add a captive portal for the guest network.

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Correct Answer: D

Explanation:
The requirement is that all external (guest) users must provide credentials before gaining wireless access. A captive portal is specifically designed for guest or external users, prompting them to authenticate or accept terms via a web page before access is granted, without requiring enterprise device configuration. Enterprise authentication (802.1X) is typically used for internal users with managed credentials and devices. Therefore, adding a captive portal for the guest network best meets the requirement.

Question 130

A network engineer runs ipconfig and notices that the default gateway is 0.0.0.0. Which of the following address types is in use?

A. APIPA

B. Multicast

C. Class C

D. Experimental

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Correct Answer: A

Explanation:
A default gateway of 0.0.0.0 commonly appears when a host is using an APIPA address (169.254.0.0/16). APIPA is assigned automatically when DHCP fails, and no default gateway is configured, resulting in 0.0.0.0 being shown.

Question 131

A technician is alarmed after noticing more than 5,000 CRCs on a switchport. Which of the following should the technician do next?

A. Move to a different switchport.

B. Check for errdisable,

C. Swap out the patch cable.

D. Enable class-of-service.

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Correct Answer: C

Explanation:
A high number of CRC errors indicates corrupted frames, most commonly caused by a bad or damaged patch cable, faulty connectors, or interference. The quickest and most appropriate next step is to swap the patch cable with a known-good one to rule out a physical layer issue.

Question 132

A network administrator received reports that a 40Gb connection is saturated. The only server the administrator can use for data collection in that location has a 10Gb connection to the network. Which of the following is the best method to use on the server to determine the source of the saturation?

A. Port mirroring

B. Log aggregation

C. Flow data

D. Packet capture

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Correct Answer: C

Explanation:
A 10Gb server cannot capture or mirror a saturated 40Gb link without dropping traffic. Flow data (e.g., NetFlow/IPFIX) provides summarized traffic information such as source, destination, and volume, which is sufficient to identify which systems or applications are causing the saturation while being feasible to collect on lower-bandwidth infrastructure.

Question 133

A network technician is designing a LAN for a new facility. The company is expecting more than 300 devices to connect to the network. Which of the following masks will provide the most efficient subnet?

A. 255.255.0.0

B. 255.255.192.0

C. 255.255.254.0

D. 255.255.255.254

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Correct Answer: C

Explanation:
The network must support more than 300 hosts. A /23 mask (255.255.254.0) provides 512 total addresses with 510 usable hosts, which is sufficient while minimizing wasted addresses. The other options either provide far too many addresses (A, B) or far too few (D).

Question 134

After extremely high temperatures cause a power outage, the servers automatically shut down, even though the UPSs for the servers still have hours of battery life. Which of the following should a technician recommend?

A. Include backup power for air-conditioning units.

B. Configure door locks to automatically lock during power outages.

C. Increase UPS battery size.

D. Add an IoT-enabled thermostat.

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Correct Answer: A

Explanation:
The outage caused the air-conditioning to stop, leading to extremely high temperatures that triggered the servers to shut down for thermal protection, even though UPS batteries were still available. Providing backup power for the air-conditioning keeps the environment within safe operating temperatures, allowing servers to continue running on UPS power.

Question 135

Which of the following actions should be taken as part of the first step of the troubleshooting methodology?

A. Conduct tests to verify ideas.

B. Handle multiple problems individually.

C. Create a theory about the possible root cause.

D. Use a top-down approach.

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Correct Answer: B

Explanation:
In the standard CompTIA troubleshooting methodology, Step 1 is **Identify the problem**. This step includes gathering information and **approaching multiple problems individually** so each issue can be isolated. Conducting tests and using top‑down approaches belong to later steps, and creating a theory is explicitly Step 2.

Question 136

Which of the following is enforced through legislation?

A. AUP

B. GDPR

C. Code of conduct

D. EULA

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Correct Answer: B

Explanation:
Legislation refers to laws enacted by a governmental or legislative authority. GDPR is a binding legal regulation passed by the EU and enforced through law, with penalties for non-compliance. An AUP, code of conduct, and EULA are organizational or contractual policies, not legislation.