Laptop Sees SSID But Cannot Connect: MAC Filtering Blocking Access
A user reports that their laptop can see the company's Wi-Fi SSID but cannot connect to the network. Other users in the same area can connect without issues. The technician verifies that the laptop's wireless adapter is enabled and that the wireless security key is correct. Which of the following should the technician check NEXT?
Quick Answer
The answer is to check the MAC filtering settings on the wireless router. This is correct because when a laptop sees the SSID but cannot connect while other devices connect fine, and the security key is verified as correct, the issue is almost certainly a Layer 2 access control mechanism. MAC filtering operates by comparing the laptop’s MAC address against an allowed list on the access point; if the address is not on the list, the router refuses to complete the association, preventing the laptop from obtaining an IP address via DHCP even though the passphrase is valid. On the CompTIA A+ Core 1 220-1101 exam, this scenario tests your ability to differentiate between authentication failures (wrong password) and association failures (MAC filtering or channel mismatch). A common trap is to immediately suspect DHCP exhaustion or a bad wireless card, but since other users connect, the problem is specific to that device’s hardware identifier. Remember the memory tip: “See the SSID, key is right, but no IP? Check the MAC whitelist.”
⚠ Common exam trap
Many candidates assume a correct security key guarantees network access, overlooking that MAC filtering can block association after successful authentication, or they confuse MAC filtering with DHCP exhaustion or DNS issues.
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
✓
MAC filtering settings on the wireless router
Since other users can connect to the same SSID, the DHCP server and wireless channel are not the issue. The laptop can see the SSID and the security key is correct, so authentication is passing, but association is failing. MAC filtering blocks the laptop's MAC address at Layer 2, preventing it from obtaining an IP address even with correct credentials.
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 DHCP server to ensure IP addresses are available
Why it's wrong here
DHCP exhaustion would prevent obtaining an IP, but the laptop would usually still be able to associate with the SSID and obtain a link-local address. However, other users connecting fine makes DHCP exhaustion unlikely.
When this WOULD be correct
If multiple users in the same area cannot connect and receive IP configuration errors, checking the DHCP server for available IP addresses would be the next step.
- ✓
MAC filtering settings on the wireless router
Why this is correct
MAC filtering can prevent a specific device from connecting even if the SSID and password are correct. The technician should verify that the laptop's MAC address is allowed.
- ✗
The DNS server configuration on the laptop
Why it's wrong here
DNS would not prevent the initial connection to the Wi-Fi network. DNS issues occur after successful connection and affect name resolution, not association.
When this WOULD be correct
A user can connect to the network (obtain an IP) but cannot browse websites or access resources by name, while IP-based access works. In that case, checking DNS server configuration would be appropriate.
- ✗
Wireless channel interference from other devices
Why it's wrong here
Channel interference would typically affect all devices, not just one. Since other users connect fine, interference is an unlikely cause for this specific laptop.
When this WOULD be correct
A user reports that their laptop can see the Wi-Fi SSID but the connection is very slow or drops frequently, while other users in the same area have no issues. The technician should check for wireless channel interference from other devices as a possible cause.
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 220-1101 exam frequently reuses these exact scenarios with slightly different constraints.
✓MAC filtering settings on the wireless routerCorrect answer▾
Why this is correct
MAC filtering can prevent a specific device from connecting even if the SSID and password are correct. The technician should verify that the laptop's MAC address is allowed.
✗The DHCP server to ensure IP addresses are availableWrong answer — click to see why▾
Why this is wrong here
The issue is specific to one laptop, not multiple users, so DHCP exhaustion is unlikely; other users connect fine, indicating the DHCP server is working.
★ When this WOULD be the correct answer
If multiple users in the same area cannot connect and receive IP configuration errors, checking the DHCP server for available IP addresses would be the next step.
Why candidates choose this
Candidates may assume connectivity failure is due to IP address assignment issues, especially if they've encountered DHCP problems in the past.
✗The DNS server configuration on the laptopWrong answer — click to see why▾
Why this is wrong here
The laptop can see the SSID and the security key is correct, so connectivity to the router is established. DNS issues typically prevent name resolution, not initial connection to the network.
★ When this WOULD be the correct answer
A user can connect to the network (obtain an IP) but cannot browse websites or access resources by name, while IP-based access works. In that case, checking DNS server configuration would be appropriate.
Why candidates choose this
Candidates often confuse connectivity issues with name resolution problems, assuming DNS is a common cause of 'cannot connect' when the actual failure is at a lower layer.
✗Wireless channel interference from other devicesWrong answer — click to see why▾
Why this is wrong here
Wireless channel interference would typically cause slow speeds or intermittent disconnections, not a complete inability to connect when the SSID is visible and the security key is correct.
★ When this WOULD be the correct answer
A user reports that their laptop can see the Wi-Fi SSID but the connection is very slow or drops frequently, while other users in the same area have no issues. The technician should check for wireless channel interference from other devices as a possible cause.
Why candidates choose this
Candidates may confuse connectivity issues with performance issues, assuming that interference can prevent a connection entirely, rather than just degrading performance.
Analysis generated from the official 220-1101blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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
IPv4 Address Classes and Ranges
Key term
Wi-Fi Protected Setup
A network security feature designed to simplify the process of connecting devices to a Wi-Fi network by using a push button or PIN instead of entering the full password.
Key term
Wired Equivalent Privacy
Wired Equivalent Privacy (WEP) is a security protocol for wireless networks, designed to provide a level of data confidentiality comparable to a wired LAN.
About these practice questions
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Same concept, more angles
1 more way this is tested on 220-1101
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A user in a small office reports that their laptop cannot connect to the corporate Wi-Fi network. Other devices in the same area connect without issue. The laptop can connect to the internet when plugged into the wired Ethernet port. The technician checks the wireless adapter status and sees it is enabled and shows available networks, but the corporate SSID is not listed. Which of the following is the most likely cause?
medium- ✓ A.The wireless network is configured for 5 GHz only, and the laptop only supports 2.4 GHz.
- B.The laptop's MAC address is not allowed on the wireless network.
- C.The wireless router is not broadcasting the SSID.
- D.The laptop's Wi-Fi antenna is disconnected inside the case.
Why A: The corporate SSID is not listed on the laptop, but other devices connect fine, indicating the network exists and is reachable. If the network is configured for 5 GHz only and the laptop only supports 2.4 GHz, the laptop will not see the SSID because it cannot tune to the 5 GHz frequency band during passive or active scanning. This matches the symptom of a missing SSID while the adapter is otherwise functional.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1101 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 220-1101 exam.