Question 1,809 of 2,152
IPv6 Traffic Filtering and uRPFmediumMultiple ChoiceObjective-mapped

Quick Answer

The correct answer is that only HTTP and HTTPS traffic from 2001:db8:1::/48 is permitted outbound; all other traffic is denied. This is because the IPv6 ACL explicitly permits TCP traffic on ports 80 and 443 from the specified source prefix, followed by an implicit deny all, and when applied as an outbound traffic filter on the interface, it inspects packets leaving that interface against these sequential rules. On the Cisco CCNP ENARSI 300-410 exam, this scenario tests your understanding of IPv6 ACL sequence logic and the critical distinction that outbound ACLs filter traffic based on the source address of the departing packet, not the destination. A common trap is forgetting that the implicit deny ipv6 any any at the end blocks all other traffic, including return traffic for established sessions unless a permit statement for established connections is included. Remember the memory tip: “Outbound ACLs check the source, inbound check the destination” to avoid misapplying the filter direction.

300-410 IPv6 Traffic Filtering and uRPF Practice Question

This 300-410 practice question tests your understanding of ipv6 traffic filtering and urpf. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.

Review the following configuration:

ipv6 access-list FILTER

permit tcp 2001:db8:1::/48 any eq 80
 permit tcp 2001:db8:1::/48 any eq

443

deny ipv6 any any

interface GigabitEthernet0/3

ipv6 traffic-filter FILTER out

What is the effect of this configuration?

Question 1mediummultiple choice
Study the full IPv6 explanation →

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

Only HTTP and HTTPS traffic from 2001:db8:1::/48 is permitted outbound; all other traffic is denied.

Option A is correct because the IPv6 ACL named FILTER explicitly permits TCP traffic from source prefix 2001:db8:1::/48 to any destination on ports 80 (HTTP) and 443 (HTTPS), and then denies all other IPv6 traffic. Applied as an outbound traffic filter on GigabitEthernet0/3, this configuration restricts outbound traffic to only HTTP and HTTPS sessions originating from the specified prefix.

Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Only HTTP and HTTPS traffic from 2001:db8:1::/48 is permitted outbound; all other traffic is denied.

    Why this is correct

    The permit statements match source prefix and destination ports; the implicit deny blocks everything else.

    Related concept

    Read the scenario before looking for a memorised answer.

  • All traffic from 2001:db8:1::/48 is permitted because the ACL does not specify destination prefix.

    Why it's wrong here

    The ACL specifies destination 'any', but the port match restricts to HTTP/HTTPS only.

  • The ACL is misconfigured because 'out' should be 'in' for source-based filtering.

    Why it's wrong here

    Outbound filtering is valid; it checks source/destination as the packet exits the interface.

  • The ACL permits all traffic because the deny statement is implicit.

    Why it's wrong here

    The explicit deny at the end overrides the implicit deny but has the same effect; only permitted traffic passes.

Common exam traps

Common exam trap: answer the scenario, not the keyword

Cisco often tests the misconception that an ACL without a destination prefix permits all traffic from the source, but in reality, the permit statement still requires the specified protocol and ports to match, and the explicit deny blocks everything else.

Detailed technical explanation

How to think about this question

IPv6 traffic filters (using the ipv6 traffic-filter command) operate similarly to IPv4 ACLs but are applied per interface and direction. The ACL is evaluated in order; the first match determines the action. In this case, only TCP packets with source address in 2001:db8:1::/48 and destination port 80 or 443 are permitted; all other IPv6 traffic, including non-TCP or different ports, is denied. This is a common method to enforce a strict outbound access policy for a specific subnet.

KKey Concepts to Remember

  • Read the scenario before looking for a memorised answer.
  • Find the constraint that changes the correct option.
  • Eliminate answers that are true in general but not in this case.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Real-world example

How this comes up in practice

A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.

What to study next

Got this wrong? Here's your next step.

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

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FAQ

Questions learners often ask

What does this 300-410 question test?

IPv6 Traffic Filtering and uRPF — This question tests IPv6 Traffic Filtering and uRPF — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: Only HTTP and HTTPS traffic from 2001:db8:1::/48 is permitted outbound; all other traffic is denied. — Option A is correct because the IPv6 ACL named FILTER explicitly permits TCP traffic from source prefix 2001:db8:1::/48 to any destination on ports 80 (HTTP) and 443 (HTTPS), and then denies all other IPv6 traffic. Applied as an outbound traffic filter on GigabitEthernet0/3, this configuration restricts outbound traffic to only HTTP and HTTPS sessions originating from the specified prefix.

What should I do if I get this 300-410 question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Last reviewed: Jun 24, 2026

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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.