LPIC-1 Essential System Services and Networking Practice Question
A user reports that they cannot connect to a remote server using SSH. The administrator checks the SSH server status and it is running. Which of the following is the most likely cause?
⚠ Common exam trap
It's easy for candidates to assume a running SSH server guarantees connectivity, overlooking that a firewall can block the port even when the service is active, or they may confuse SSH's TCP usage with UDP-based protocols like DNS.
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
✓
A firewall is blocking port 22.
SSH operates over TCP port 22 by default. If the SSH server is running but the client cannot connect, a firewall blocking port 22 is the most likely cause because it would prevent the TCP handshake from completing, even though the SSH daemon (sshd) is active and listening.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
A firewall is blocking port 22.
Why this is correct
Firewall blocking SSH port is a common issue.
- ✗
The client's subnet mask is incorrect.
Why it's wrong here
This would affect local network, not remote server.
- ✗
The client cannot resolve the server's hostname.
Why it's wrong here
This would cause a different error.
- ✗
The SSH server is using UDP instead of TCP.
Why it's wrong here
SSH uses TCP.
Visual reference
Go deeper
Related to this question
About these practice questions
This LPIC-1 question is part of Courseiva's 527-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This LPIC-1 practice question is part of Courseiva's free LPI 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 LPIC-1 exam.