Quick Answer
The answer is to enable STP protection features like BPDU guard, disable unused ports, and use VLANs. Disabling unused ports prevents unauthorized physical access and eliminates the risk of an attacker connecting to an open port to launch attacks such as ARP spoofing or DHCP starvation, while VLANs segment traffic to contain threats, and BPDU guard protects the spanning-tree topology from rogue switches. On the ISC2 Certified in Cybersecurity CC exam, this question tests your understanding of network switch security best practices as part of the Network Security domain, often appearing as a multi-select scenario where a common trap is choosing port security or MAC filtering instead of BPDU guard—remember that BPDU guard is specifically for STP protection, not general access control. A helpful memory tip is “DVB”: Disable unused ports, VLANs for segmentation, and BPDU guard for loop prevention.
This CC practice question tests your understanding of network security. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which three of the following are best practices for securing a network switch? (Choose three.)
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "best"
Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Enable Telnet for remote management.
Why wrong: Telnet transmits credentials in cleartext; use SSH.
Disable unused ports.
Reduces attack surface.
Use VLANs to segment traffic.
Limits broadcast domains and improves security.
Enable STP protection features like BPDU guard.
Prevents rogue switch attacks.
Set all ports to trunk mode by default.
Why wrong: Trunking should be disabled on access ports to prevent VLAN hopping.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Disable unused ports.
Disabling unused ports on a network switch prevents unauthorized physical access and eliminates the risk of an attacker connecting to an open port to launch attacks such as ARP spoofing or DHCP starvation. This is a fundamental security best practice that reduces the attack surface by ensuring that only necessary ports are active and can be administratively controlled.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Enable Telnet for remote management.
Disable unused ports.
Why this is correct
Reduces attack surface.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Use VLANs to segment traffic.
Why this is correct
Limits broadcast domains and improves security.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Enable STP protection features like BPDU guard.
Why this is correct
Prevents rogue switch attacks.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Set all ports to trunk mode by default.
Why it's wrong here
Trunking should be disabled on access ports to prevent VLAN hopping.
Common exam traps
ISC2 often tests the misconception that Telnet is acceptable for management if a password is set, but the exam expects you to recognize that Telnet lacks encryption and is therefore never a best practice for securing a switch.
Detailed technical explanation
STP protection features like BPDU guard immediately error-disable a port if it receives a Bridge Protocol Data Unit (BPDU), preventing rogue switches from being introduced into the network and causing topology changes or loops. VLANs provide Layer 2 segmentation by logically isolating traffic, which limits broadcast domains and contains threats like broadcast storms or malware propagation to a single VLAN. In a real-world scenario, an attacker plugging a laptop into an unused port could launch a DHCP rogue server attack, but disabling the port or placing it in a shutdown VLAN mitigates this risk.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A security analyst at a medium-sized enterprise encounters this scenario during an investigation or architecture review. The correct answer reflects best practice for the specific threat or control described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Security exam questions test whether you can match controls to threats in context — not just recall definitions.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Network Security — This question tests Network Security — Read the scenario before looking for a memorised answer..
The correct answer is: Disable unused ports. — Disabling unused ports on a network switch prevents unauthorized physical access and eliminates the risk of an attacker connecting to an open port to launch attacks such as ARP spoofing or DHCP starvation. This is a fundamental security best practice that reduces the attack surface by ensuring that only necessary ports are active and can be administratively controlled.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 30, 2026
This CC practice question is part of Courseiva's free ISC2 certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CC exam.
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