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 /26 subnet mask divides the IP address space into blocks of 64 addresses, with 26 bits for the network and 6 bits for hosts.. 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 host address is 172.16.8.70/26. What is the network address of its subnet?
172.16.8.0
Why wrong: This is wrong because 70 is not in the 0–63 block.
172.16.8.64
This is correct because 70 falls within the 64–127 /26 block.
172.16.8.70
Why wrong: This is wrong because 70 is the host address, not the network address.
172.16.8.128
Why wrong: This is wrong because the 128 block begins above the host address.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
172.16.8.64
A /26 uses blocks of 64 addresses. In plain language, the fourth-octet subnet ranges are 0–63, 64–127, 128–191, and 192–255. Since the host address ends in 70, it belongs to the 64–127 block. That means the network address of the subnet is 172.16.8.64. This is a standard subnetting calculation. The key is to identify the correct block based on the prefix and then choose the first address in that block as the network address.
Key principle: A /26 subnet mask divides the IP address space into blocks of 64 addresses, with 26 bits for the network and 6 bits for hosts.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
172.16.8.0
Why it's wrong here
This is wrong because 70 is not in the 0–63 block.
When this WOULD be correct
If the question asked for the network address of the subnet for a host address of 172.16.8.70 with a subnet mask of /24, then 172.16.8.0 would be the correct answer, as it represents the beginning of that subnet.
172.16.8.64
Why this is correct
This is correct because 70 falls within the 64–127 /26 block.
Related concept
A /26 subnet mask divides the IP address space into blocks of 64 addresses, with 26 bits for the network and 6 bits for hosts.
172.16.8.70
Why it's wrong here
This is wrong because 70 is the host address, not the network address.
When this WOULD be correct
If the question asked for the specific host address within the subnet or if it was framed to identify a host's IP address rather than the network address, then 172.16.8.70 would be the correct answer.
172.16.8.128
Why it's wrong here
This is wrong because the 128 block begins above the host address.
When this WOULD be correct
In a different question, if the subnet mask were changed to /25, the network address would be 172.16.8.128. For example, a question asking for the network address of the subnet containing the host 172.16.8.130 with a /25 mask would make this option correct.
Option-by-option analysis
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.
Why this is correct
This is correct because 70 falls within the 64–127 /26 block.
Why this is wrong here
The /26 prefix means a subnet mask of 255.255.255.192, which creates subnets with a block size of 64. The subnet ranges are 0–63, 64–127, 128–191, and 192–255. Since 70 is not in the 0–63 range, 172.16.8.0 is not the correct network address.
★ When this WOULD be the correct answer
If the question asked for the network address of the subnet for a host address of 172.16.8.70 with a subnet mask of /24, then 172.16.8.0 would be the correct answer, as it represents the beginning of that subnet.
Why candidates choose this
Students often mistakenly assume that the network address is always the first address of the entire /16 or /24 network, ignoring the subnetting. They might think 172.16.8.0 is the network address because it is the first address in the 172.16.8.0/24 range.
Why this is wrong here
The network address is the first address in a subnet, where all host bits are 0. The address 172.16.8.70 has host bits that are not all zeros; it is a valid host address within the subnet 172.16.8.64/26. Therefore, it cannot be the network address.
★ When this WOULD be the correct answer
If the question asked for the specific host address within the subnet or if it was framed to identify a host's IP address rather than the network address, then 172.16.8.70 would be the correct answer.
Why candidates choose this
A student might confuse the host address with the network address, especially if they are not careful about the distinction between the two. They might think that the given IP address itself is the network address.
Why this is wrong here
The subnet 172.16.8.128/26 covers addresses 128–191. Since 70 is less than 128, it does not belong to this subnet. The network address for the subnet containing 70 is 172.16.8.64, not 172.16.8.128.
★ When this WOULD be the correct answer
In a different question, if the subnet mask were changed to /25, the network address would be 172.16.8.128. For example, a question asking for the network address of the subnet containing the host 172.16.8.130 with a /25 mask would make this option correct.
Why candidates choose this
Students sometimes miscalculate the subnet boundaries, especially when the host address is near the boundary. They might incorrectly think that 70 is close to 128 and choose 172.16.8.128 without performing the proper calculation.
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
A frequent exam trap is mistaking the host IP address for the network address or selecting the wrong subnet block based on the subnet mask. Candidates often pick 172.16.8.0 because it looks like a common network address or 172.16.8.128 assuming it’s the next block, but these do not contain the host 172.16.8.70 under a /26 mask. The trap arises from not calculating subnet ranges correctly or misunderstanding how subnet masks segment the address space into fixed blocks. This mistake leads to incorrect subnet identification and can cause routing or addressing errors in real networks.
Detailed technical explanation
Subnetting is a fundamental concept in IP networking that divides a larger network into smaller, manageable subnetworks. Each subnet has a unique network address and a range of host addresses. The subnet mask, expressed in CIDR notation like /26, determines how many bits are used for the network portion versus the host portion of the IP address. In this case, /26 means the first 26 bits are the network part, leaving 6 bits for host addresses, which allows for 64 addresses per subnet. To find the network address of a given host IP with a /26 mask, you identify the subnet block that contains the host. Since each /26 subnet covers 64 addresses, the subnet ranges in the fourth octet are 0–63, 64–127, 128–191, and 192–255. The host address 172.16.8.70 falls within the 64–127 range, so the network address is 172.16.8.64. The network address is always the first address in the subnet block and cannot be assigned to a host. A common exam trap is confusing the host address with the network address or selecting the wrong subnet block. For example, choosing 172.16.8.0 or 172.16.8.128 ignores the actual block boundaries defined by the subnet mask. In practical Cisco networking, correctly identifying subnet boundaries ensures proper routing and IP address management, preventing IP conflicts and routing errors within VLANs or routed interfaces.
Key takeaway
A /26 subnet mask divides the IP address space into blocks of 64 addresses, with 26 bits for the network and 6 bits for hosts.
Real-world example
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
Review a /26 subnet mask divides the IP address space into blocks of 64 addresses, with 26 bits for the network and 6 bits for hosts., then practise related 200-301 questions on the same topic to reinforce the concept.
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FAQ
Network Infrastructure and Connectivity — This question tests Network Infrastructure and Connectivity — A /26 subnet mask divides the IP address space into blocks of 64 addresses, with 26 bits for the network and 6 bits for hosts..
The correct answer is: 172.16.8.64 — A /26 uses blocks of 64 addresses. In plain language, the fourth-octet subnet ranges are 0–63, 64–127, 128–191, and 192–255. Since the host address ends in 70, it belongs to the 64–127 block. That means the network address of the subnet is 172.16.8.64. This is a standard subnetting calculation. The key is to identify the correct block based on the prefix and then choose the first address in that block as the network address.
Review a /26 subnet mask divides the IP address space into blocks of 64 addresses, with 26 bits for the network and 6 bits for hosts., then practise related 200-301 questions on the same topic to reinforce the concept.
A /26 subnet mask divides the IP address space into blocks of 64 addresses, with 26 bits for the network and 6 bits for hosts.
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Last reviewed: May 17, 2026
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