mediumMultiple Choice
350-401 Practice Question: Consider the following configuration: router…
Consider the following configuration:
router eigrp 100 network 10.0.0.0 0.255.255.255 passive-interface default no passive-interface GigabitEthernet0/0
Which statement is true about this EIGRP configuration?
⚠ Common exam trap
Cisco often tests the interaction between `passive-interface default` and `no passive-interface` to see if candidates understand that the default passive setting overrides all interfaces except those explicitly enabled, rather than the reverse.
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
✓
EIGRP will send and receive updates only on GigabitEthernet0/0.
The `passive-interface default` command sets all interfaces to passive by default, preventing EIGRP from sending or receiving hello packets (and thus updates) on them. The `no passive-interface GigabitEthernet0/0` command then overrides this default for that specific interface, allowing EIGRP to send and receive updates only on GigabitEthernet0/0. The network statement 10.0.0.0 0.255.255.255 enables EIGRP on any interface matching the 10.0.0.0/8 range, but the passive-interface logic restricts actual adjacency formation.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
EIGRP will send and receive updates only on GigabitEthernet0/0.
Why this is correct
Because the router is configured with passive-interface default, every interface is placed in passive mode by default, meaning EIGRP will not send or process updates on them. The 'no passive-interface GigabitEthernet0/0' command explicitly removes that passive designation only for GigabitEthernet0/0, allowing EIGRP to both send and receive updates on that single interface. As a result, EIGRP adjacency and update exchange occur exclusively on Gi0/0, exactly as the correct answer states, while all other interfaces remain passive and do not participate in EIGRP.
- ✗
EIGRP will send updates on all interfaces except GigabitEthernet0/0.
Why it's wrong here
This option reverses the effect of the passive-interface default and the no passive-interface override. With passive-interface default enabled, all interfaces start in passive mode; only GigabitEthernet0/0 is explicitly taken out of passive mode via 'no passive-interface GigabitEthernet0/0', so Gi0/0 is the only active interface. Therefore, EIGRP sends updates only on Gi0/0, not on all interfaces except Gi0/0. The phrase 'except GigabitEthernet0/0' directly contradicts the configuration, which enables EIGRP on Gi0/0 and disables it everywhere else.
- ✗
EIGRP will not send any updates because the network statement is incorrect.
Why it's wrong here
The EIGRP network statement 10.0.0.0 0.255.255.255 is valid; the wildcard mask correctly matches the entire 10.0.0.0/8 range, so EIGRP is enabled on any interface whose IP address falls within that range. The router's failure to send updates on other interfaces is not due to a malformed network statement, but because the passive-interface default command suppresses all interfaces unless specifically overridden. Therefore, the claim that the network statement is incorrect is false; the configuration is syntactically and logically correct, just constrained by the passive-interface default behavior.
- ✗
EIGRP will form adjacencies on all interfaces that have an IP address in the 10.0.0.0/8 range.
Why it's wrong here
While the network statement 10.0.0.0 0.255.255.255 would normally enable EIGRP on all interfaces with an IP in the 10.0.0.0/8 range, the global 'passive-interface default' command prevents EIGRP from sending hello packets or forming adjacencies on those interfaces. EIGRP only forms adjacencies on interfaces where it can send and receive hello packets, and passive interfaces do not participate in that process. Since only GigabitEthernet0/0 has been explicitly set to 'no passive-interface', it is the sole interface where adjacencies can form; all other interfaces with 10.x.x.x addresses remain passive and cannot establish EIGRP neighbors.
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 350-401 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 350-401 exam.