Static Route Not Active Due to Unreachable Next-Hop
A network administrator configures a static route on a Juniper device: `set routing-options static route 192.168.100.0/24 next-hop 10.0.0.1`. The administrator verifies the route is present in the routing table but notices it is not active. What is the most likely cause?
Quick Answer
The answer is that the static route is not active because the next-hop address 10.0.0.1 is unreachable. On Junos, a static route will only be installed as an active route in the forwarding table if its next-hop is reachable through a directly connected interface or another active route; if the next-hop is not resolvable via ARP or an existing route, Junos marks the static route as hidden or inactive. This concept directly tests your understanding of Junos route resolution logic on the JNCIA-Junos exam, where a common trap is assuming a static route becomes active simply by being configured—it must have a valid, reachable next-hop. A frequent exam scenario presents a static route present in the configuration but missing from the active route table, and the correct diagnosis is always to check next-hop reachability. Memory tip: think “No hop, no go”—if the next-hop isn’t reachable, the route stays hidden.
⚠ Common exam trap
Candidates often assume a static route is always active once configured and committed, overlooking Junos's requirement that the next-hop must be reachable via an active directly connected route for the route to be installed as active.
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
✓
The next-hop address 10.0.0.1 is not reachable.
A static route becomes active only if the next-hop address is reachable via a directly connected or active route in the routing table. Since the administrator verified the route is present but not active, the most likely cause is that the next-hop 10.0.0.1 is not reachable (e.g., no ARP resolution or no interface with that subnet). Junos marks such routes as hidden or inactive until the next hop is reachable.
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 is not committed.
Why it's wrong here
If the route were not committed, it would not appear in the routing table.
- ✓
The next-hop address 10.0.0.1 is not reachable.
Why this is correct
If the next-hop is not in the routing table, the static route is not active.
- ✗
The preference of the static route is higher than 15.
Why it's wrong here
Static routes default preference is 5; a higher preference number makes it less preferred, but it does not cause inactivity by itself.
- ✗
The destination prefix is already learned via OSPF with a lower metric.
Why it's wrong here
OSPF metric is not compared across protocols; route preference determines active route.
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Same concept, more angles
4 more ways this is tested on JN0-106
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Refer to the exhibit. A network administrator configured a static route to 10.0.0.0/24 with next-hop 192.168.1.1. The route is not appearing in the active routing table. What is the most likely reason?
hard- ✓ A.The next-hop address is not reachable.
- B.The route is a reject route.
- C.The route is being overridden by an OSPF route with lower preference.
- D.The static route preference is too high.
Why A: The exhibit shows that the route's next-hop type is 'Unreachable', indicating that the next-hop address 192.168.1.1 is not reachable. Since the next-hop is unreachable, the static route cannot be installed in the active routing table. Option B is incorrect because a reject route would show 'Reject' or 'Discard'. Option C is incorrect: even if an OSPF route existed with lower preference (higher priority), the static route would still appear as a backup; the problem here is next-hop unreachability. Option D is incorrect: a static route with preference 5 is low, meaning it is highly preferred; high preference would make it less preferred, but the route is not active due to unreachable next-hop, not preference.
Variation 2. An administrator configures a static route to 192.168.2.0/24 with next-hop 10.0.0.1. The route does not appear in the routing table. What is the most likely cause?
easy- ✓ A.The next-hop 10.0.0.1 is not reachable.
- B.The static route has a higher preference than an existing dynamic route.
- C.The configuration was not committed.
- D.The prefix 192.168.2.0/24 already exists in the forwarding table.
Why A: A static route will only be installed in the routing table if the next-hop address is reachable via an active route in the routing table. If 10.0.0.1 is not reachable (e.g., no route to that subnet, or the interface is down), Junos will reject the static route and not place it in the inet.0 table. This is a fundamental validation check in Junos that prevents black-hole routing.
Variation 3. A network administrator configures the following: `set routing-options static route 0.0.0.0/0 next-hop 192.168.1.1`. After committing, the administrator notices that the default route is not active. What could be the reason?
medium- A.The route preference is set to 170.
- B.The route is not exported into the forwarding table.
- ✓ C.The next-hop 192.168.1.1 is not reachable.
- D.The router already has a default route learned via DHCP.
Why C: A static route becomes active only if the next-hop address is reachable via a directly connected interface or another active route. If 192.168.1.1 is not reachable (e.g., interface down, no matching subnet, or no route to the next-hop), the route remains hidden (inactive) in the routing table. Junos verifies next-hop reachability before installing a static route into the forwarding table.
Variation 4. A static route is configured with next-hop 10.0.0.1, but the route does not appear in the routing table. The interface ge-0/0/0 has IP 192.168.1.2/24 and is up. What is the most likely reason?
medium- A.The static route has a preference of 5.
- B.The route is hidden due to an import policy.
- C.The static route is configured with the 'discard' option.
- ✓ D.The next-hop IP is not on a directly connected subnet.
Why D: D is correct because Junos requires the next-hop IP of a static route to be reachable via a directly connected subnet for the route to be installed in the routing table. Since the next-hop 10.0.0.1 is not on the same subnet as the interface ge-0/0/0 (192.168.1.2/24), the route remains hidden and does not appear in the routing table.
JA
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.