This LFCS practice question tests your understanding of user and group management. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
Exhibit
Refer to the exhibit:
$ cat /etc/passwd | grep alice
alice:x:1001:1001:Alice Smith:/home/alice:/bin/bash
$ ls -ld /home/alice
drwxr-x--- 2 root root 4096 Jan 10 10:00 /home/alice
Refer to the exhibit. User 'alice' cannot log in. What is the most likely problem?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Refer to the exhibit:
$ cat /etc/passwd | grep alice
alice:x:1001:1001:Alice Smith:/home/alice:/bin/bash
$ ls -ld /home/alice
drwxr-x--- 2 root root 4096 Jan 10 10:00 /home/alice
A
The shadow file is missing alice's entry
Why wrong: The 'x' in passwd indicates shadow entry exists; otherwise it would be blank or other.
B
The user's UID or GID is not unique
Why wrong: Uniqueness is not a direct cause of login failure.
C
The home directory ownership is incorrect
Home directory should be owned by alice:alice, not root:root.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The home directory ownership is incorrect
Option B is correct because the home directory is owned by root, not alice. Many systems use PAM modules like pam_umask that require the home directory to be owned by the user. Option A: shadow entry seems valid (x indicates password in shadow). Option C: shell is /bin/bash which is valid. Option D: UID exists and matches; GID is 1001, group may exist but missing group entry affects group permissions, not login directly.
Key principle: Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
The shadow file is missing alice's entry
Why it's wrong here
The 'x' in passwd indicates shadow entry exists; otherwise it would be blank or other.
✗
The user's UID or GID is not unique
Why it's wrong here
Uniqueness is not a direct cause of login failure.
✓
The home directory ownership is incorrect
Why this is correct
Home directory should be owned by alice:alice, not root:root.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Detailed technical explanation
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
CIDR notation defines the prefix length.
Block size helps identify subnet boundaries.
Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
The required host count determines the smallest suitable subnet.
TExam Day Tips
→Write the block size before choosing the subnet.
→Check whether the question asks for hosts, subnets or a specific address range.
→Do not confuse /24, /25, /26 and /27 host counts.
Key takeaway
Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
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 block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related LFCS subnetting questions on CIDR, address ranges, and subnet selection.
User and Group Management — This question tests User and Group Management — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: The home directory ownership is incorrect — Option B is correct because the home directory is owned by root, not alice. Many systems use PAM modules like pam_umask that require the home directory to be owned by the user. Option A: shadow entry seems valid (x indicates password in shadow). Option C: shell is /bin/bash which is valid. Option D: UID exists and matches; GID is 1001, group may exist but missing group entry affects group permissions, not login directly.
What should I do if I get this LFCS question wrong?
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related LFCS subnetting questions on CIDR, address ranges, and subnet selection.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
CIDR notation defines the prefix length.
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