SK0-005 troubleshooting Practice Question
A server administrator is troubleshooting a network connectivity issue where a newly installed server cannot communicate with other devices on the same subnet. The server has a static IP address configured. Other devices on the same switch can communicate. Which TWO of the following could be the cause of the issue? (Select TWO)
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
✓
The switch port is configured with port security and has learned a different MAC address.
Options A and B are correct. An incorrect subnet mask (A) would cause the server to misinterpret which IPs are local, preventing communication with devices on the same subnet. Port security on the switch (B) could block traffic if the learned MAC address does not match. Option C (default gateway) is irrelevant for same-subnet communication. Option D (DNS) affects name resolution, not basic IP connectivity. Option E (DHCP) is not used since the server has a static IP.
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 DNS server address is incorrect.
Why it's wrong here
Incorrect DNS prevents name resolution but does not stop IP communication between devices using IP addresses.
- ✗
The server's default gateway is incorrectly set.
Why it's wrong here
The default gateway is used for traffic destined to other networks; same-subnet communication does not involve the gateway.
- ✓
The switch port is configured with port security and has learned a different MAC address.
Why this is correct
Port security limits allowed MAC addresses; if the port sees the new server's MAC, it may block the frames if the maximum is exceeded or the address is not authorized.
- ✓
Incorrect subnet mask configured on the server.
Why this is correct
With a wrong mask, the server might think a local address is remote and send traffic to the default gateway, causing communication failure with local devices.
- ✗
The DHCP server has exhausted its scope.
Why it's wrong here
DHCP exhaustion only affects devices requesting IPs; this server has a static IP, so DHCP is not involved.
Visual reference
Quick reference
Access Control Model Comparison
| Model | Acronym | Who Controls Access? | Best For |
|---|---|---|---|
| Discretionary Access Control | DAC | Resource owner | Small teams, file shares |
| Mandatory Access Control | MAC | System / security labels | Classified govt / military |
| Role-Based Access Control | RBAC | Administrator (via roles) | Enterprise environments |
| Attribute-Based Access Control | ABAC | Policy engine (user + resource attributes) | Fine-grained, dynamic policies |
| Rule-Based Access Control | RuBAC | System rules / ACLs | Firewall rules, network ACLs |
Go deeper
Related to this question
Learn chapter
Network Configuration and Connectivity
Key term
DNS
DNS is the system that translates human-friendly domain names like example.com into machine-readable IP addresses so computers can find each other on a network.
Key term
Security
Security in IT is the practice of protecting systems, networks, and data from unauthorized access, damage, or theft.
About these practice questions
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed July 2026 · checked against the official CompTIA exam blueprint
This SK0-005 practice question is part of Courseiva's free CompTIA 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 SK0-005 exam.