mediumMultiple ChoiceObjective-mapped
300-410 Practice Question: Which statement accurately describes the default…
Which statement accurately describes the default behavior of auto-summary in EIGRP on Cisco IOS-XE?
⚠ Common exam trap
Cisco often tests the misconception that auto-summary is still enabled by default in EIGRP on modern IOS-XE, when in fact it was changed to disabled by default starting from IOS 15.0(1)M and later.
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
✓
Auto-summary is disabled by default, and EIGRP advertises subnets without automatic summarization.
In Cisco IOS-XE, EIGRP auto-summary is disabled by default. This means that EIGRP advertises subnets without automatically summarizing them at classful boundaries, allowing for more granular route advertisement and preventing routing issues in discontiguous networks.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Auto-summary is enabled by default, causing EIGRP to summarize at classful boundaries.
Why it's wrong here
This was true in older IOS versions, but auto-summary is now disabled by default in IOS-XE.
- ✓
Auto-summary is disabled by default, and EIGRP advertises subnets without automatic summarization.
Why this is correct
Correct. IOS-XE defaults to no auto-summary, preserving subnet information.
- ✗
Auto-summary is enabled by default but only for external routes.
Why it's wrong here
Auto-summary applies to all EIGRP routes, not just external ones, and it is disabled by default.
- ✗
Auto-summary is disabled by default unless the network is configured with a classful mask.
Why it's wrong here
The default is disabled regardless of the network mask configuration.
Visual reference
Quick reference
Routing Protocol Comparison
| Protocol | Metric | Max Hops | Algorithm | Type |
|---|---|---|---|---|
| RIP v2 | Hop count | 15 | Bellman-Ford | Distance vector |
| OSPF | Cost (bandwidth) | Unlimited | Dijkstra (SPF) | Link state |
| EIGRP | Composite metric | Unlimited | DUAL | Hybrid |
| IS-IS | Cost | Unlimited | Dijkstra | Link state |
| BGP | Policy / attributes | Unlimited | Path vector | Path vector |
RIP's 15-hop limit makes it unsuitable for large networks. OSPF and EIGRP dominate modern enterprise deployments.
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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.