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200-201 A security analyst reviews the firewall log Practice Question
Network Topology
A security analyst reviews the firewall log. What is the most likely reason for the denied connection?
⚠ Common exam trap
Cisco often tests the concept that the implicit deny at the end of an ACL is the most common reason for denied traffic, tempting candidates to overthink with threat-based answers like external IPs or malicious hosts.
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 access control list does not permit the traffic
The firewall log shows a denied connection, and the most likely reason is that the access control list (ACL) does not permit the traffic. Firewalls enforce security policies by evaluating traffic against ACL rules; if no rule explicitly allows the packet (based on source/destination IP, port, and protocol), the implicit deny at the end of the ACL drops the connection. This is the default behavior for stateful firewalls and is the most common cause of denied connections in logs.
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 port is blocked by default
Why it's wrong here
Port 80 is not blocked by default.
- ✗
The source IP address is an external threat
Why it's wrong here
Source IP is internal.
- ✗
The destination IP is a known malicious host
Why it's wrong here
No evidence of malicious destination.
- ✓
The access control list does not permit the traffic
Why this is correct
Denied by access-group indicates ACL blocking.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-201 practice question is part of Courseiva's free Cisco 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 200-201 exam.