Quick Answer
The answer is that the command is rejected without a direction keyword. In Cisco IOS, the access-group command requires an explicit direction parameter—either in or out—to define whether the ACL filters traffic entering or leaving the interface. This is because the direction is a mandatory argument, not an optional one; omitting it triggers an error message rather than defaulting to a specific direction. On the Cisco CCNP ENARSI 300-410 exam, this tests your precise knowledge of ACL application syntax, often appearing as a trick where candidates assume a default direction like “in” exists. A common trap is confusing the access-group command with other Cisco features that do have defaults, such as the ip access-group command on VLAN interfaces in some older platforms. To avoid this pitfall, remember the mnemonic: “No direction, no connection”—if you don’t specify in or out, the router will reject the command outright.
This 300-410 practice question tests your understanding of ipv4 access control lists. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
When using the 'access-group' command to apply an ACL to an interface, what is the default direction if none is specified?
Inbound
Why wrong: No default direction; the keyword is mandatory.
Outbound
Why wrong: No default direction; the keyword is mandatory.
The command defaults to inbound.
Why wrong: Cisco IOS requires explicit direction.
The command is rejected without a direction keyword.
The access-group command syntax requires either 'in' or 'out'.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
The command is rejected without a direction keyword.
The 'access-group' command in Cisco IOS requires a direction keyword (either 'in' or 'out') to specify whether the ACL filters inbound or outbound traffic. If no direction is provided, the command is rejected with an error message because the direction is a mandatory parameter. This behavior is consistent across all Cisco IOS versions and platforms.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Inbound
Why it's wrong here
No default direction; the keyword is mandatory.
Outbound
Why it's wrong here
No default direction; the keyword is mandatory.
The command defaults to inbound.
Why it's wrong here
Cisco IOS requires explicit direction.
The command is rejected without a direction keyword.
Why this is correct
The access-group command syntax requires either 'in' or 'out'.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
The trap here is that Cisco often tests the misconception that ACLs default to inbound when no direction is specified, but the command is actually rejected without the mandatory keyword.
Trap categories for this question
Keyword trap
No default direction; the keyword is mandatory.
Detailed technical explanation
The 'access-group' command is applied under interface configuration mode, and the direction keyword determines whether the ACL is evaluated for packets entering ('in') or leaving ('out') the interface. Without the keyword, the CLI parser fails with an incomplete command error, as the direction is a required argument. In real-world scenarios, forgetting the direction can cause ACLs to be unintentionally omitted, leading to security gaps or traffic misrouting.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A security administrator must allow nursing staff to reach a patient records server while blocking access from the guest Wi-Fi VLAN. After applying an extended ACL, traffic is still blocked from nursing workstations. The ACL was applied outbound instead of inbound on the wrong interface. Questions like this test ACL direction and placement rules.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
IPv4 Access Control Lists — study guide chapter
Learn the concepts, then practise the questions
IPv4 Access Control Lists practice questions
Targeted practice on this topic area only
All 300-410 questions
2,152 questions across all exam domains
Cisco CCNP ENARSI 300-410 study guide
Full concept coverage aligned to exam objectives
300-410 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise 300-410 questions linked to Layer 3 Technologies.
Practise 300-410 questions linked to EIGRP Troubleshooting.
Practise 300-410 questions linked to OSPF Troubleshooting (v2/v3).
Practise 300-410 questions linked to BGP Troubleshooting.
Practise 300-410 questions linked to Route Redistribution.
Practise 300-410 questions linked to Policy-Based Routing (PBR).
Practise 300-410 questions linked to VRF-Lite.
Practise 300-410 questions linked to Route Maps and Route Filtering.
Practise 300-410 questions linked to Administrative Distance.
Practise 300-410 questions linked to Route Summarization.
Practise 300-410 questions linked to Bidirectional Forwarding Detection (BFD).
Practise 300-410 questions linked to VPN Technologies.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
IPv4 Access Control Lists — This question tests IPv4 Access Control Lists — Read the scenario before looking for a memorised answer..
The correct answer is: The command is rejected without a direction keyword. — The 'access-group' command in Cisco IOS requires a direction keyword (either 'in' or 'out') to specify whether the ACL filters inbound or outbound traffic. If no direction is provided, the command is rejected with an error message because the direction is a mandatory parameter. This behavior is consistent across all Cisco IOS versions and platforms.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jun 24, 2026
This 300-410 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 300-410 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.