JN0-106 Routing Fundamentals Practice Question
A network administrator configures a default route using 'set routing-options static route 0.0.0.0/0 next-hop 10.0.0.1 preference 10' and later enables OSPF which also advertises a default route with default preference 150. Which route becomes active in the routing table?
⚠ Common exam trap
A common mix-up: candidates think OSPF always overrides static routes or that both routes can be used for ECMP, but Junos uses preference values to select a single active route, and ECMP only applies when preferences are equal.
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
✓
Static route to 0.0.0.0/0 with next-hop 10.0.0.1
The static route has a preference of 10, which is lower than OSPF's default preference of 150. Junos uses the route with the lowest preference value as the active route in the routing table. Therefore, the static default route becomes active.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Neither route becomes active due to conflicting protocols
Why it's wrong here
This choice is incorrect. A routing table never ignores both candidates merely because they come from different protocols. Junos uses route preference (administrative distance) to break ties; since one route must have a lower preference, it is chosen as active, and the other remains as a backup in the routing table.
- ✗
Both routes are active for ECMP load balancing
Why it's wrong here
ECMP cannot apply here. Equal-cost multipath requires multiple routes with the same preference and equal metric to be installed simultaneously. Static and OSPF default routes have different route preferences (10 vs. 150), so only the route with the better preference is selected; the other is held as inactive, not load-balanced.
- ✓
Static route to 0.0.0.0/0 with next-hop 10.0.0.1
Why this is correct
The static route to 0.0.0.0/0 with next-hop 10.0.0.1 is the winning route. With a route preference of 10, it is more trustworthy than the OSPF default route’s preference of 150. Junos installs it in the inet.0 routing table and destination table, so it becomes the active default route.
- ✗
OSPF route to 0.0.0.0/0
Why it's wrong here
The OSPF default route has a higher route preference (150), meaning it is considered less trustworthy than the static route. Although OSPF may have learned and installed the route, it is kept as an inactive alternative because a better-preference route exists. It would only become active if the static default route were removed or had a worse preference.
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 JN0-106 practice question is part of Courseiva's free Juniper Networks 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 JN0-106 exam.