Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
A subnet uses the prefix /29. How many usable host addresses are available in each subnet?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
2
This is wrong because 2 usable addresses would be far too small for a /29.
B
Best answer
6
This is correct because a /29 has 8 total addresses and 6 usable host addresses.
C
Distractor review
14
This is wrong because 14 usable hosts would correspond to a /28.
D
Distractor review
30
This is wrong because 30 usable hosts would correspond to a /27.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is mistaking the total number of addresses in a subnet for the number of usable host addresses. Candidates often see that a /29 subnet has 8 total addresses and incorrectly select 8 or a number close to it without subtracting the network and broadcast addresses. This mistake leads to overestimating the number of hosts that can be assigned IPs, which is incorrect in Cisco subnetting rules. Remember, usable hosts always exclude these two reserved addresses, so the correct usable count for /29 is 6, not 8.
Technical deep dive
How to think about this question
Subnetting divides a larger IP network into smaller, manageable segments called subnets. The prefix length, such as /29, indicates how many bits are used for the network portion of the address, leaving the remaining bits for host addressing. In IPv4, a /29 prefix means 29 bits are fixed for the network, and 3 bits remain for host addresses, since IPv4 addresses are 32 bits total. The total number of addresses in a /29 subnet is 2^3 = 8 addresses. However, two addresses in every subnet are reserved: one for the network identifier (all host bits zero) and one for the broadcast address (all host bits one). This leaves 6 usable host addresses for devices. Cisco CCNA exams expect candidates to calculate usable hosts by subtracting these two reserved addresses from the total. A common exam trap is to confuse total addresses with usable hosts, leading to incorrect answers like 8 or 14. Practically, understanding this distinction is critical for designing IP addressing schemes in Cisco networks, ensuring efficient use of address space and avoiding address conflicts or broadcast issues.
KKey Concepts to Remember
- A /29 subnet mask uses 29 bits for the network portion and leaves 3 bits for host addressing in IPv4.
- The total number of IP addresses in a /29 subnet is 8, calculated as 2 to the power of 3 host bits.
- Two IP addresses in every subnet are reserved: one for the network ID and one for the broadcast address.
- Usable host addresses equal total addresses minus the network and broadcast addresses, resulting in 6 for a /29 subnet.
- Cisco CCNA exam questions require subtracting reserved addresses to find usable hosts, not just calculating total addresses.
- Confusing total addresses with usable hosts is a common exam trap that leads to incorrect subnetting answers.
- Subnetting efficiently divides IP address space and helps in designing scalable Cisco networks with proper host allocation.
- Understanding subnetting fundamentals is essential for configuring VLANs, routing, and ACLs in Cisco network environments.
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.
Related practice questions
Related 200-301 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
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CCNA IPv6 practice questions
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
A /29 subnet mask uses 29 bits for the network portion and leaves 3 bits for host addressing in IPv4.
What is the correct answer to this question?
The correct answer is: 6 — A /29 prefix leaves 3 host bits, which creates 8 total addresses per subnet. In plain language, two of those addresses cannot be assigned to hosts because one identifies the subnet itself and one is reserved as the broadcast address. That leaves 6 usable host addresses. This is a standard CCNA calculation because it checks whether you understand both the total address count and the subtraction of the reserved addresses. Many candidates remember powers of two but forget to account for the network and broadcast addresses when the question asks for usable hosts. The safest process is to calculate the total size first and then reduce it by two. That is how you arrive at 6 usable addresses for a /29.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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