LFCS Networking Practice Question
A server has two NICs bonded in mode 1 (active-backup). If the active NIC fails, what occurs?
⚠ Common exam trap
It's easy for candidates to confuse active-backup (mode 1) with balance-rr (mode 0) or assume that both NICs must be active for redundancy, leading them to incorrectly select Option A.
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
✓
Traffic automatically switches to the backup NIC with minimal interruption
In bonding mode 1 (active-backup), only one NIC is active at a time while the other remains in standby. When the active NIC fails, the bonding driver automatically fails over to the backup NIC by reassigning the MAC address and IP to the backup interface, typically within a few milliseconds. This ensures minimal interruption to network traffic without requiring manual intervention.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Both NICs continue to pass traffic simultaneously
Why it's wrong here
Mode 1 permits only one slave to transmit at a time; the backup stays idle until failover. It is tempting because simultaneous transmission describes mode 0 (balance-rr) or 802.3ad, where aggregation spreads traffic across links, but active-backup deliberately serialises them for switch-independent redundancy.
- ✓
Traffic automatically switches to the backup NIC with minimal interruption
Why this is correct
Mode 1 active-backup bonding keeps the backup NIC passive until the active link fails. Failover detection then moves the MAC and traffic to the backup interface, maintaining connectivity with only brief interruption, satisfying the redundancy requirement.
- ✗
The bond interface goes down until an administrator intervenes
Why it's wrong here
Mode 1 automatically fails over to the standby NIC within milliseconds, so the bond stays up and traffic continues; no administrative action is needed. It is tempting because a bond with no viable slave does go down, but that requires both NICs to fail, not just the active one.
- ✗
The system disables the bond and uses a single NIC
Why it's wrong here
The bond interface persists and the standby NIC simply becomes active; the kernel never dissolves the bond or reverts to unmanaged single-NIC operation. It is tempting because failover does leave one NIC carrying traffic, but that NIC remains a bonded slave, not a standalone interface.
Quick reference
Access Control Model Comparison
| Model | Acronym | Who Controls Access? | Best For |
|---|---|---|---|
| Discretionary Access Control | DAC | Resource owner | Small teams, file shares |
| Mandatory Access Control | MAC | System / security labels | Classified govt / military |
| Role-Based Access Control | RBAC | Administrator (via roles) | Enterprise environments |
| Attribute-Based Access Control | ABAC | Policy engine (user + resource attributes) | Fine-grained, dynamic policies |
| Rule-Based Access Control | RuBAC | System rules / ACLs | Firewall rules, network ACLs |
Go deeper
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This LFCS practice question is part of Courseiva's free Linux Foundation 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 LFCS exam.