mediumMultiple SelectObjective-mapped
300-410 Practice Question: Which TWO configuration steps are required to…
Which TWO configuration steps are required to enable EIGRP authentication between two directly connected routers? (Choose TWO.)
⚠ Common exam trap
Cisco often tests the misconception that EIGRP authentication is configured under the router process (like OSPF) rather than on the interface, leading candidates to incorrectly select Option B.
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
✓
Configure a key chain with a key string on both routers.
EIGRP authentication requires a key chain to be configured on both routers, which defines the key string (the actual password) used for authentication. Without a matching key string in the key chain, the authentication process will fail, as the routers cannot validate each other's EIGRP packets.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Configure a key chain with a key string on both routers.
Why this is correct
The key chain defines the authentication key; it must be created globally with at least one key and a key string.
- ✗
Apply the authentication mode and key chain under the EIGRP router process.
Why it's wrong here
EIGRP authentication is configured under the interface, not the router process.
- ✓
Use the 'ip authentication mode eigrp <as> md5' command on the connecting interfaces.
Why this is correct
This interface command enables MD5 authentication for EIGRP on that interface.
- ✗
Set the same autonomous system number in the key chain configuration.
Why it's wrong here
The key chain does not use the AS number; the AS is specified in the interface authentication commands.
- ✗
Ensure the key chain name is different on each router to prevent conflicts.
Why it's wrong here
The key chain name must match on both routers for authentication to succeed.
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.
Go deeper
Related to this question
Learn chapter
EIGRP Neighbor Adjacency and Basics
Key term
EIGRP Authentication
EIGRP authentication is a security feature that verifies the identity of routers exchanging routing information to prevent unauthorized or malicious updates.
Key term
OSPF and EIGRP Authentication
OSPF and EIGRP authentication is a security feature that verifies the identity of routers exchanging routing updates, ensuring only trusted devices can participate in the network.
About these practice questions
One of 1,966 original 300-410 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
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.