hardMultiple ChoiceObjective-mapped
300-410 Practice Question: An engineer configures DHCPv6 prefix delegation…
An engineer configures DHCPv6 prefix delegation on a router with multiple requesting interfaces. The router receives a /48 prefix from the server, but only one interface gets a /64 sub-prefix. Which is the most likely explanation?
⚠ Common exam trap
Cisco often tests the distinction between receiving a delegated prefix and actually assigning sub-prefixes to interfaces, trapping candidates who assume that receiving a /48 automatically gives every interface a /64.
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 one interface is configured with 'ipv6 address prefix-name ::1:0:0:0:1/64' using the delegated prefix; other interfaces lack this configuration.
The router receives a /48 prefix from the DHCPv6 server, but each requesting interface must explicitly reference the delegated prefix using the 'ipv6 address prefix-name' command to derive a /64 sub-prefix. If only one interface has this configuration, only that interface will obtain a /64 sub-prefix; the other interfaces lack the necessary command to consume the delegated prefix.
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 one interface is configured with 'ipv6 address prefix-name ::1:0:0:0:1/64' using the delegated prefix; other interfaces lack this configuration.
Why this is correct
Correct: The delegated prefix must be explicitly used on each interface with the appropriate 'ipv6 address' command referencing the prefix name.
- ✗
The DHCPv6 server only delegates a single /64 prefix, not a /48.
Why it's wrong here
Incorrect: The question states a /48 is received.
- ✗
The router's 'ipv6 dhcp client pd' command is missing the 'rapid-commit' option.
Why it's wrong here
Incorrect: Rapid commit speeds up the process but does not affect the number of interfaces.
- ✗
The router has 'ipv6 dhcp client information refresh' set to a high value, delaying updates.
Why it's wrong here
Incorrect: This affects lease renewal, not the initial assignment.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.