mediumMultiple ChoiceObjective-mapped
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 ip eigrp topology 10.1.1.0/24
IP-EIGRP (AS 100): Topology entry for 10.1.1.0/24 State: Passive, Originating reply status: 0 Routing Descriptor Blocks:
0.0.0.0 (Null0), from 0.0.0.0, Send flag: 0x0
Composite metric is (2560000000/0), Route is Internal Vector metric: Minimum bandwidth is 100000 Kbit Total delay is 100 microseconds Reliability is 255/255 Load is 1/255 Minimum MTU is 1500 Hop count is 0
10.2.2.2 (GigabitEthernet0/1), from 10.2.2.2, Send flag: 0x0
Composite metric is (2688000000/2560000000), Route is Internal Vector metric: Minimum bandwidth is 100000 Kbit Total delay is 200 microseconds Reliability is 255/255 Load is 1/255 Minimum MTU is 1500 Hop count is 1
Based on this output, what is the problem?
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
✓
A manual summary route is configured on R1 for 10.1.1.0/24, causing a local Null0 entry.
The output shows a Null0 entry with a metric of 2560000000/0, which is characteristic of a summary route. The problem is that an EIGRP summary route is being advertised, but the route is also learned from another neighbor (10.2.2.2) with a higher metric, indicating potential suboptimal routing or a missing 'no auto-summary' command.
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 route 10.1.1.0/24 is redistributed from another protocol into EIGRP.
Why it's wrong here
The route is marked as Internal, not External, so it is not redistributed.
- ✓
A manual summary route is configured on R1 for 10.1.1.0/24, causing a local Null0 entry.
Why this is correct
The Null0 entry with metric 2560000000/0 indicates a summary route; the 'ip summary-address eigrp' command creates this entry to prevent loops.
- ✗
The route 10.1.1.0/24 is flapping between Passive and Active states.
Why it's wrong here
The state is Passive, indicating stability, not flapping.
- ✗
The neighbor 10.2.2.2 is not reachable, so the route is installed via Null0.
Why it's wrong here
The neighbor is reachable as shown by the Routing Descriptor Block, and the Null0 entry is for the summary, not due to unreachability.
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.