mediumMultiple Choice
300-410 Practice Question: Runs the following command on Router R1: R1# show…
A network engineer runs the following command on Router R1:
R1# show ipv6 interface gigabitethernet 0/0 | include uRPF
IPv6 uRPF: strict mode
Based on this output, which statement is true?
⚠ Common exam trap
Cisco often tests the distinction between strict and loose uRPF modes, and the trap here is that candidates might confuse the 'strict mode' output with 'loose mode' or assume uRPF is disabled when the output line is present.
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
✓
uRPF is enabled in strict mode
The command output explicitly shows 'IPv6 uRPF: strict mode', which confirms that unicast Reverse Path Forwarding (uRPF) is enabled and operating in strict mode. In strict mode, the router verifies that the source address of an incoming packet matches a route in the FIB and that the incoming interface is the same as the outgoing interface for that route. This prevents spoofed traffic from entering the network.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
uRPF is disabled
Why it's wrong here
Strict mode is enabled, so uRPF is not disabled; the output explicitly reports "IPv6 uRPF: strict mode" on the interface. Disabled interfaces omit this line entirely. The option tempts engineers who assume uRPF defaults to off unless configured, which holds on interfaces where no uRPF command was applied — but here the running configuration already shows strict mode active.
- ✓
uRPF is enabled in strict mode
Why this is correct
The output states IPv6 uRPF: strict mode, confirming unicast reverse path forwarding is enabled in strict mode. Strict mode drops packets unless the source address is reachable via the same interface they arrived on, satisfying the verification shown in the command output.
- ✗
uRPF is enabled in loose mode
Why it's wrong here
Loose mode accepts any source address present in the routing table, regardless of the ingress interface, so it would not be reported as strict. The output explicitly states strict mode, which requires the source to be reachable via the receiving interface. Loose mode suits asymmetric routing, where return traffic arrives on a different path.
- ✗
uRPF is enabled but only for multicast
Why it's wrong here
The output states strict mode, which applies to unicast source addresses; multicast traffic is not validated by uRPF at all, so the claim contradicts the displayed configuration. It tempts because uRPF does interact with multicast through specific commands, but that would appear as a separate multicast-specific line, not as strict mode.
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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.