PCNSA Device Management and Services Practice Question
A network administrator wants to allow FTP traffic from the internal network to a specific external server. The administrator creates a security policy rule with source zone 'internal', destination zone 'external', destination IP of the server, and application 'ftp'. However, the traffic is still blocked. What is the most likely reason?
⚠ Common exam trap
Test-takers frequently assume a simple 'allow' rule for the application 'ftp' is sufficient, overlooking that FTP's dual-channel nature requires the firewall to perform deep packet inspection to dynamically permit the data channel ports negotiated in passive mode.
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 FTP application requires additional configuration for passive mode
FTP uses two separate channels: a control channel (TCP 21) and a data channel. In passive mode, the client initiates both connections, but the data channel uses a random high port negotiated via the control channel. The Palo Alto Networks firewall's application decoder for FTP must inspect the control channel to dynamically open pinholes for the data channel; without this, the data connection is blocked even if the control channel is allowed. Option D is correct because the administrator likely created a rule for application 'ftp' but did not ensure that the FTP application's passive mode data connections are properly handled, which requires the firewall to perform application-level inspection and create temporary security policy openings for the negotiated data ports.
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 destination IP is not covered by a NAT policy
Why it's wrong here
NAT is not required for outbound FTP.
- ✗
Logging is not enabled on the rule
Why it's wrong here
Logging does not affect whether traffic is allowed.
- ✗
The rule is set to deny instead of allow
Why it's wrong here
The administrator created the rule to allow.
- ✓
The FTP application requires additional configuration for passive mode
Why this is correct
FTP uses dynamic ports; the firewall needs to inspect control channel to allow data channel.
Visual reference
Go deeper
Related to this question
About these practice questions
This PCNSA question is part of Courseiva's 516-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 PCNSA practice question is part of Courseiva's free Palo Alto Networks 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 PCNSA exam.