Question 173 of 1,819
Network Infrastructure and ConnectivityhardMultiple ChoiceObjective-mapped

CCNA Network Infrastructure and Connectivity Practice Question

This 200-301 practice question tests your understanding of network infrastructure and connectivity. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. A key principle to apply: a subnet mask of 255.255.255.252 corresponds to a /30 prefix length in IPv4 addressing.. 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.

A subnet uses the mask 255.255.255.252. How many usable host addresses are available in each subnet?

Question 1hardmultiple choice
Review the full subnetting walkthrough →

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

2

The mask 255.255.255.252 corresponds to /30. In practical terms, that gives 4 total addresses per subnet. After subtracting the network and broadcast addresses, 2 usable host addresses remain. This is a classic small-subnet calculation that often appears in point-to-point addressing scenarios.

Key principle: A subnet mask of 255.255.255.252 corresponds to a /30 prefix length in IPv4 addressing.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • 2

    Why this is correct

    This is correct because /30 provides 4 total addresses and 2 usable hosts.

    Related concept

    A subnet mask of 255.255.255.252 corresponds to a /30 prefix length in IPv4 addressing.

  • 4

    Why it's wrong here

    This is wrong because that is the total number of addresses, not the usable host count.

    When this WOULD be correct

    If the question asked for the total number of addresses in a subnet instead of usable addresses, then the answer would be 4, as it accounts for all IP addresses in the subnet, including the network and broadcast addresses.

  • 6

    Why it's wrong here

    This is wrong because /30 subnets do not provide 6 usable hosts.

    When this WOULD be correct

    If the question specified a subnet mask of 255.255.255.248 instead, which allows for 6 usable host addresses, then option C would be correct. This mask provides 8 total addresses, with 2 reserved for network and broadcast.

  • 14

    Why it's wrong here

    This is wrong because 14 usable hosts corresponds to a /28 subnet.

    When this WOULD be correct

    If the question were to ask about a subnet mask of 255.255.255.240, which allows for 16 total addresses, the usable host addresses would be 14. In this case, option D would be the correct answer.

Option-by-option analysis

Why each answer is right or wrong

Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.

2Correct answer

Why this is correct

This is correct because /30 provides 4 total addresses and 2 usable hosts.

4Wrong answer — click to see why

Why this is wrong here

The /30 subnet provides a total of 4 addresses, but one is the network address and one is the broadcast address, leaving only 2 usable host addresses. Saying 4 is incorrect because it counts the network and broadcast addresses as usable.

★ When this WOULD be the correct answer

If the question asked for the total number of addresses in a subnet instead of usable addresses, then the answer would be 4, as it accounts for all IP addresses in the subnet, including the network and broadcast addresses.

Why candidates choose this

Students often confuse the total number of addresses in a subnet with the number of usable host addresses. Since 2^2 = 4, they may mistakenly think all 4 are available for hosts.

6Wrong answer — click to see why

Why this is wrong here

A /30 subnet has only 2 bits for host addresses, yielding 2^2 = 4 total addresses, of which 2 are usable. 6 usable hosts would require at least 3 host bits (2^3 - 2 = 6), which corresponds to a /29 subnet.

★ When this WOULD be the correct answer

If the question specified a subnet mask of 255.255.255.248 instead, which allows for 6 usable host addresses, then option C would be correct. This mask provides 8 total addresses, with 2 reserved for network and broadcast.

Why candidates choose this

Some test-takers might incorrectly apply the formula 2^n - 2 and think n=3 gives 6, but they forget that /30 has only 2 host bits, not 3.

14Wrong answer — click to see why

Why this is wrong here

14 usable hosts correspond to a /28 subnet (255.255.255.240), which has 4 host bits (2^4 - 2 = 14). A /30 subnet has only 2 host bits, so it cannot provide 14 usable hosts.

★ When this WOULD be the correct answer

If the question were to ask about a subnet mask of 255.255.255.240, which allows for 16 total addresses, the usable host addresses would be 14. In this case, option D would be the correct answer.

Why candidates choose this

Students may confuse the subnet mask 255.255.255.252 with 255.255.255.240, as both are common masks, and mistakenly apply the host count of a /28 to a /30.

Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”

Common exam traps

Common exam trap: answer the scenario, not the keyword

Remember to exclude network and broadcast addresses when calculating usable host addresses.

Detailed technical explanation

How to think about this question

Subnetting is a fundamental concept in IP networking that divides a larger network into smaller, manageable segments called subnets. The subnet mask 255.255.255.252 corresponds to a /30 prefix length, which means the first 30 bits are fixed for the network portion, leaving only 2 bits for host addressing. This small subnet size is commonly used in point-to-point links where only two devices need to communicate directly. The calculation for usable hosts in a subnet follows the formula 2^n - 2, where n is the number of host bits. For a /30 mask, n equals 2, so 2^2 = 4 total addresses. Subtracting the network address and broadcast address leaves 2 usable host IP addresses. Cisco devices and CCNA exams expect candidates to recognize this pattern quickly, as /30 subnets are standard for efficient IP address allocation in WAN links. A common exam trap is confusing total addresses with usable host addresses. Candidates might see 4 total addresses and mistakenly select 4 as usable hosts, ignoring that the network and broadcast addresses cannot be assigned to hosts. Practically, this means that a /30 subnet is ideal for point-to-point links but unsuitable for larger LAN segments requiring more hosts.

KKey Concepts to Remember

  • A subnet mask of 255.255.255.252 corresponds to a /30 prefix length in IPv4 addressing.
  • A /30 subnet provides 4 total IP addresses, including network and broadcast addresses.
  • Usable host addresses in a subnet are calculated by subtracting network and broadcast addresses from total addresses.
  • The formula 2^n - 2 determines usable hosts, where n is the number of host bits in the subnet mask.
  • In a /30 subnet, only 2 usable host addresses are available for device assignment.
  • Cisco CCNA exams expect candidates to distinguish between total IP addresses and usable host addresses in subnetting questions.
  • Point-to-point links commonly use /30 subnets to efficiently allocate IP addresses with minimal waste.
  • Misinterpreting total addresses as usable hosts is a frequent exam trap in subnetting questions.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

A subnet mask of 255.255.255.252 corresponds to a /30 prefix length in IPv4 addressing.

Real-world example

How this comes up in practice

A network engineer segments a warehouse floor into three subnets: 20 scanners, 5 printers, and 2 management hosts. Picking the wrong mask wastes addresses or leaves too few usable hosts. Exam questions test whether you can apply CIDR notation, calculate block size, and identify the correct usable-host range for a given prefix.

What to study next

Got this wrong? Here's your next step.

Review a subnet mask of 255.255.255.252 corresponds to a /30 prefix length in IPv4 addressing., then practise related 200-301 questions on the same topic to reinforce the concept.

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FAQ

Questions learners often ask

What does this 200-301 question test?

Network Infrastructure and Connectivity — This question tests Network Infrastructure and Connectivity — A subnet mask of 255.255.255.252 corresponds to a /30 prefix length in IPv4 addressing..

What is the correct answer to this question?

The correct answer is: 2 — The mask 255.255.255.252 corresponds to /30. In practical terms, that gives 4 total addresses per subnet. After subtracting the network and broadcast addresses, 2 usable host addresses remain. This is a classic small-subnet calculation that often appears in point-to-point addressing scenarios.

What should I do if I get this 200-301 question wrong?

Review a subnet mask of 255.255.255.252 corresponds to a /30 prefix length in IPv4 addressing., then practise related 200-301 questions on the same topic to reinforce the concept.

What is the key concept behind this question?

A subnet mask of 255.255.255.252 corresponds to a /30 prefix length in IPv4 addressing.

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Last reviewed: May 17, 2026

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