CCNA Network Services and Security Practice Question
Network Topology
You are connected to R1. The network uses a single router with two subnets: 192.168.1.0/24 (connected to GigabitEthernet0/0) and 10.0.0.0/30 (connected to GigabitEthernet0/1). Configure an extended named ACL called 'FILTER_HTTP' that permits HTTP traffic (TCP port 80) from the 192.168.1.0/24 subnet to any destination, and includes an explicit deny statement to deny all other IP traffic. Apply the ACL inbound on GigabitEthernet0/0. Then verify that HTTP traffic is allowed and all other traffic is blocked.
⚠ Common exam trap
Pay attention to the requirement for a named ACL versus numbered ACL. Also, note that while the implicit deny exists, the question explicitly asks for a deny statement, so you must include it. Finally, ensure the ACL is applied to the correct interface and direction.
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
✓
ip access-list extended FILTER_HTTP permit tcp 192.168.1.0 0.0.0.255 any eq 80 deny ip any any interface GigabitEthernet0/0 ip access-group FILTER_HTTP in
The task requires creating an extended named ACL 'FILTER_HTTP' that permits TCP port 80 from source 192.168.1.0/24 to any destination, and then denies all other IP traffic (the implicit deny will block everything else, but you must explicitly add a deny ip any any statement to make the intent clear). The ACL must be applied inbound on GigabitEthernet0/0. The solution uses the commands: ip access-list extended FILTER_HTTP, permit tcp 192.168.1.0 0.0.0.255 any eq 80, deny ip any any, and interface GigabitEthernet0/0, ip access-group FILTER_HTTP in. Verification with show access-lists and show ip interface GigabitEthernet0/0 confirms the ACL and its application.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
ip access-list extended FILTER_HTTP permit tcp 192.168.1.0 0.0.0.255 any eq 80 deny ip any any interface GigabitEthernet0/0 ip access-group FILTER_HTTP in
Why this is correct
This sequence correctly creates an extended named ACL that permits HTTP (TCP port 80) from the 192.168.1.0/24 subnet to any destination, explicitly denies all other IP traffic, and applies the ACL inbound on GigabitEthernet0/0. The explicit deny ip any any ensures that the intent is clear and that all non-HTTP traffic is blocked.
- ✗
access-list 100 permit tcp 192.168.1.0 0.0.0.255 any eq 80 access-list 100 deny ip any any interface GigabitEthernet0/0 ip access-group 100 in
Why it's wrong here
This configuration uses a numbered extended ACL (access-list 100) instead of the named extended ACL 'FILTER_HTTP' that the question explicitly requires. While numbered ACL 100 can filter traffic and would work functionally if applied, the exam scenario demands a named ACL, and using a numbered ACL does not satisfy the stated requirement. Additionally, the syntax 'ip access-group 100 in' references the numbered ACL, which further confirms it is not the named ACL requested.
- ✗
ip access-list extended FILTER_HTTP permit tcp 192.168.1.0 0.0.0.255 any eq 80 interface GigabitEthernet0/0 ip access-group FILTER_HTTP in
Why it's wrong here
This is incorrect because it omits the explicit deny ip any any statement. While the implicit deny at the end of the ACL will block all other traffic, the question explicitly states 'denies all other IP traffic', so an explicit deny is required to make the intent clear.
- ✗
ip access-list extended FILTER_HTTP permit tcp 192.168.1.0 0.0.0.255 any eq 80 deny ip any any interface GigabitEthernet0/1 ip access-group FILTER_HTTP in
Why it's wrong here
This configuration defines the named ACL 'FILTER_HTTP' correctly with the permit and explicit deny statements, but it applies the ACL inbound on interface GigabitEthernet0/1 rather than GigabitEthernet0/0. The requirement specifies that the ACL must be applied inbound on GigabitEthernet0/0, which is the interface connected to the 192.168.1.0/24 subnet. Applying it on the wrong interface means that traffic from that subnet entering via G0/0 will not be filtered, leaving the network unprotected and failing the requirement.
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 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓ip access-list extended FILTER_HTTP permit tcp 192.168.1.0 0.0.0.255 any eq 80 deny ip any any interface GigabitEthernet0/0 ip access-group FILTER_HTTP inCorrect answer▾
Why this is correct
This sequence correctly creates an extended named ACL that permits HTTP (TCP port 80) from the 192.168.1.0/24 subnet to any destination, explicitly denies all other IP traffic, and applies the ACL inbound on GigabitEthernet0/0. The explicit deny ip any any ensures that the intent is clear and that all non-HTTP traffic is blocked.
✗access-list 100 permit tcp 192.168.1.0 0.0.0.255 any eq 80 access-list 100 deny ip any any interface GigabitEthernet0/0 ip access-group 100 inWrong answer — click to see why▾
Why this is wrong here
The specific factual error is that the ACL must be named 'FILTER_HTTP', but this option uses a numbered ACL (100).
Why candidates choose this
Candidates might pick this because they know that extended ACLs can be numbered (100-199) and the permit/deny statements are correct, but they overlook the requirement for a named ACL.
✗ip access-list extended FILTER_HTTP permit tcp 192.168.1.0 0.0.0.255 any eq 80 interface GigabitEthernet0/0 ip access-group FILTER_HTTP inWrong answer — click to see why▾
Why this is wrong here
The specific factual error is that the ACL does not include an explicit deny ip any any, which is needed to satisfy the requirement of denying all other IP traffic.
Why candidates choose this
Candidates might pick this because they know that ACLs have an implicit deny, so they think an explicit deny is unnecessary. However, the question explicitly requires a deny statement.
✗ip access-list extended FILTER_HTTP permit tcp 192.168.1.0 0.0.0.255 any eq 80 deny ip any any interface GigabitEthernet0/1 ip access-group FILTER_HTTP inWrong answer — click to see why▾
Why this is wrong here
The specific factual error is that the ACL is applied to the wrong interface (GigabitEthernet0/1 instead of GigabitEthernet0/0).
Why candidates choose this
Candidates might pick this because they confuse the two interfaces or think that applying the ACL on the other interface might also work, but the direction and interface must match the requirement.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-301 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 200-301 exam.