220-1101 Networking Practice Question
A user reports that after a power outage and router restart, their desktop computer can no longer access network shares on other computers. The user can access the internet. The technician runs ipconfig and sees the IP address changed from 192.168.1.50 to 192.168.1.75. The other computers on the network have static IP addresses. Which of the following should the technician configure to resolve the issue permanently?
⚠ Common exam trap
A common mix-up: candidates choose 'Configure a static IP address' (Option A) because it seems straightforward, but the CompTIA exam tests the understanding that DHCP reservations are the preferred method for permanent IP assignment in a DHCP-enabled network to maintain centralized control and avoid conflicts.
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
✓
Configure a DHCP reservation on the router for the user's computer.
The user's IP address changed from 192.168.1.50 to 192.168.1.75 after the router restart, indicating the computer received a new DHCP lease. Since other computers use static IPs, the user's computer likely had a static IP before the outage but reverted to DHCP after the restart, or it was always using DHCP and the router assigned a different address. Configuring a DHCP reservation on the router ensures the router always assigns the same IP (192.168.1.50) to the user's MAC address, permanently resolving the connectivity issue to network shares without changing the computer's configuration.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Configure a static IP address on the user's computer.
Why it's wrong here
Configuring a static IP on the user's computer would indeed keep the address constant, but it removes the device from DHCP management, requiring manual local configuration and documentation. Without also adding an exclusion or reservation on the router, the DHCP server may still lease that same address to another device, resulting in an IP conflict that disrupts connectivity. The user would need administrative rights on the PC, and every network change (DNS, gateway) must be manually updated, making it less flexible than a DHCP reservation.
When this WOULD be correct
In a scenario where the network does not have a DHCP server (e.g., all devices use static IPs) and the user's computer needs a fixed IP to access resources, configuring a static IP address on the user's computer would be the correct solution.
- ✓
Configure a DHCP reservation on the router for the user's computer.
Why this is correct
A DHCP reservation binds a specific IP address to the computer's MAC address on the router. This ensures the computer always obtains the same IP via DHCP, preventing address changes while maintaining centralized IP management.
- ✗
Set a shorter DHCP lease time on the router.
Why it's wrong here
Setting a shorter DHCP lease time accelerates the rate at which clients renegotiate their IP addresses, so after a reboot or router restart the user's computer can easily be handed a different address from the pool. A lease only defines the duration of an assigned address, not its uniqueness or reservation; a short lease expires quickly and increases the chance the router's next offer differs from the previous lease. This directly aggravates the problem of a changing IP, rather than stabilizing it.
When this WOULD be correct
In a scenario where a network has a limited pool of IP addresses and devices frequently disconnect and reconnect, a shorter DHCP lease time can help reclaim unused addresses more quickly, preventing address exhaustion.
- ✗
Change the subnet mask to 255.255.0.0.
Why it's wrong here
Changing the subnet mask to 255.255.0.0 transforms the network from a /24 to a /16, expanding the broadcast domain to 65,534 hosts. This does not bind the user's PC to a particular IP; it merely tells the computer that many more addresses are local, which breaks ARP and routing because the router and other devices still operate on the original /24 subnet. Worse, it can cause the computer to send traffic directly instead of through the gateway, causing connectivity failures, while leaving the DHCP pool unchanged.
When this WOULD be correct
A technician is asked to connect two separate networks (e.g., 192.168.1.0/24 and 192.168.2.0/24) without a router, and devices need to communicate directly. Changing the subnet mask to 255.255.0.0 on all devices would make them see each other as local.
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.
✓Configure a DHCP reservation on the router for the user's computer.Correct answer▾
Why this is correct
A DHCP reservation binds a specific IP address to the computer's MAC address on the router. This ensures the computer always obtains the same IP via DHCP, preventing address changes while maintaining centralized IP management.
✗Configure a static IP address on the user's computer.Wrong answer — click to see why▾
Why this is wrong here
The user's IP address changed from 192.168.1.50 to 192.168.1.75, indicating DHCP is assigning addresses. Other computers have static IPs, so the user's computer likely needs a consistent IP to access network shares. Configuring a static IP on the user's computer would work but is not the best practice for a network with DHCP; a DHCP reservation is preferred to avoid conflicts and ease management.
★ When this WOULD be the correct answer
In a scenario where the network does not have a DHCP server (e.g., all devices use static IPs) and the user's computer needs a fixed IP to access resources, configuring a static IP address on the user's computer would be the correct solution.
Why candidates choose this
Candidates may think setting a static IP is the simplest way to ensure the IP doesn't change, overlooking that a DHCP reservation achieves the same result without manual configuration on each device and reduces the risk of IP conflicts.
✗Set a shorter DHCP lease time on the router.Wrong answer — click to see why▾
Why this is wrong here
Setting a shorter DHCP lease time would cause the IP address to change more frequently, which does not solve the problem of the user's computer losing access to network shares after a power outage. The issue is that the computer's IP address changed from a previously used address, and a shorter lease would only exacerbate address changes.
★ When this WOULD be the correct answer
In a scenario where a network has a limited pool of IP addresses and devices frequently disconnect and reconnect, a shorter DHCP lease time can help reclaim unused addresses more quickly, preventing address exhaustion.
Why candidates choose this
Candidates might think that a shorter lease time would make the IP address change less disruptive or that it would force the router to reassign the same address, but they overlook that the core issue is the need for a fixed address, not the lease duration.
✗Change the subnet mask to 255.255.0.0.Wrong answer — click to see why▾
Why this is wrong here
Changing the subnet mask to 255.255.0.0 would expand the network to 192.168.0.0/16, which is unnecessary and could cause routing issues or security concerns. The problem is IP address conflict due to DHCP assigning a different address, not subnet mask mismatch.
★ When this WOULD be the correct answer
A technician is asked to connect two separate networks (e.g., 192.168.1.0/24 and 192.168.2.0/24) without a router, and devices need to communicate directly. Changing the subnet mask to 255.255.0.0 on all devices would make them see each other as local.
Why candidates choose this
Candidates may think that since the user can access the internet but not local shares, the subnet mask is wrong, or they confuse subnet mask with gateway settings.
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 |
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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.