hardMultiple ChoiceObjective-mapped
220-1201 Practice Question: A company deploys a new internal application that…
A company deploys a new internal application that uses a custom TCP port. The application fails to connect from client workstations. A technician verifies that the server is running and the firewall allows outbound traffic. Which step should the technician take next to identify the port issue?
⚠ Common exam trap
Some candidates may think that ping or general network connectivity tests are sufficient to diagnose port-specific issues, but the trap here is that ICMP and TCP operate at different layers, and only a port-level check like netstat can confirm whether the application is listening on the correct TCP port.
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
✓
Run netstat on the server to see if the application is listening on the correct port.
The technician needs to verify that the application is actually listening on the expected custom TCP port. Running `netstat -an` on the server will show all listening ports and their states; if the application's port is not listed, the application may be bound to a different port or not started correctly, which is a common cause of connection failures even when the server is running and outbound traffic is allowed.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Run netstat on the server to see if the application is listening on the correct port.
Why this is correct
Running netstat on the server is the most direct method to verify if the new application is actively listening for incoming connections on its designated port. This command displays active network connections, listening ports, and routing tables, allowing an administrator to confirm that the application process has successfully bound to the expected TCP or UDP port. If netstat does not show the application listening, it indicates a server-side configuration issue or that the application failed to start correctly, preventing client connections.
- ✗
Ping the server from a client to test network connectivity.
Why it's wrong here
Pinging the server from a client only tests basic network layer (Layer 3) connectivity using ICMP. A successful ping confirms that the server is reachable by its IP address and that the network path between the client and server is operational. However, it does not provide any insight into whether a specific application service is running or listening on a particular TCP or UDP port, which is essential for application-level communication. Therefore, a successful ping does not guarantee the application is accessible.
- ✗
Use nslookup to verify the server's hostname resolves correctly.
Why it's wrong here
Nslookup is a command-line tool used to query DNS (Domain Name System) servers for hostname-to-IP address resolution. While proper DNS resolution is a fundamental prerequisite for clients to locate a server by its name, nslookup provides no information about the server's port status or whether an application is actively listening on a specific port. It addresses the name resolution aspect, not the application's readiness to accept connections on the transport layer.
- ✗
Check the DHCP lease to ensure the client has a valid IP address.
Why it's wrong here
Checking the DHCP lease on the client ensures that the client device has successfully obtained a valid IP address, subnet mask, and other necessary network configuration details from a DHCP server. While a valid IP address is crucial for any network communication, this action focuses solely on the client's network configuration and does not provide any information about the server's application status or whether its services are listening on the correct port. It addresses client-side network setup, not server-side application availability.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1201 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 220-1201 exam.