easyMultiple 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 snmp mib ifmib ifindex
ifIndex: 1
Interface: GigabitEthernet0/0
Description: GigabitEthernet0/0
ifIndex: 2
Interface: GigabitEthernet0/1
Description: GigabitEthernet0/1
ifIndex: 3
Interface: Loopback0
Description: Loopback0
ifIndex: 10
Interface: Tunnel0
Description: Tunnel0
Based on this output, which statement is correct?
⚠ Common exam trap
Cisco often tests the misconception that ifIndex values are assigned sequentially starting from 0 or 1 without gaps, but the output shows non-sequential values (e.g., Tunnel0 with ifIndex 10) to trap candidates who assume a simple 1-to-1 order.
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
✓
The ifIndex for Loopback0 is 3.
The output of 'show snmp mib ifmib ifindex' displays the ifIndex values assigned to each interface by the SNMP agent. The table clearly shows Loopback0 with ifIndex 3, making option A correct. ifIndex values are not guaranteed to be sequential or start from 0; they are assigned dynamically and can have gaps, as seen with Tunnel0 having ifIndex 10.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The ifIndex for Loopback0 is 3.
Why this is correct
The output lists each interface with its assigned ifIndex, and Loopback0 is explicitly shown as ifIndex 3. This directly satisfies the question's requirement to identify the correct mapping from the `show snmp mib ifmib ifindex` command, confirming the persistent index used for SNMP polling of that interface.
- ✗
The ifIndex values are assigned sequentially starting from 0.
Why it's wrong here
The output shows ifIndex 1, 2, 3 then 10, so values are not sequential from 0; interface indices are assigned per interface and need not be contiguous. Sequential numbering from 0 is tempting because many people assume SNMP indices increment predictably, but the ifmib ifindex table simply reports each interface's assigned index.
- ✗
GigabitEthernet0/0 has ifIndex 2.
Why it's wrong here
GigabitEthernet0/0 is listed with ifIndex 1; ifIndex 2 belongs to GigabitEthernet0/1. Reading the wrong line is tempting because the two physical interfaces are consecutive entries with similar names, but the ifmib ifindex output binds each index to the interface named immediately beneath it.
- ✗
Tunnel0 has ifIndex 3.
Why it's wrong here
The listing pairs ifIndex 3 with Loopback0, not Tunnel0, which holds ifIndex 10. Confusing the two is tempting because both are logical interfaces and appear adjacent in the output, but the ifmib ifindex mapping is explicit: each interface's index is the number printed directly above its name.
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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.