JN0-106 Routing Fundamentals Practice Question
An administrator wants to drop traffic destined to the 10.10.10.0/24 network without sending an ICMP unreachable message back to the source. Which static route option should be used?
⚠ Common exam trap
Watch out — candidates often confuse 'reject' with 'discard' because both drop traffic, but they fail to remember that 'reject' sends an ICMP unreachable message, which the question explicitly prohibits.
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
✓
discard
The 'discard' static route option silently drops traffic destined to the 10.10.10.0/24 network without generating any ICMP unreachable message. This is in contrast to the 'reject' option, which drops traffic but sends an ICMP unreachable back to the source. The 'discard' route is ideal for blackholing unwanted traffic while avoiding unnecessary network feedback.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
reject
Why it's wrong here
The reject next-hop type in Junos discards the packet but also sends an ICMP unreachable (host unreachable) message back to the source. For an administrator who wants to drop traffic to 10.10/16, reject may reveal the filtering action and can cause extra control-plane load from generating ICMP responses. Because the requirement is simply to drop the traffic, reject is not the correct action.
- ✓
discard
Why this is correct
The discard next-hop type installs a route that silently drops the packet without sending any ICMP response. The forwarding engine discards the traffic in the data plane, so it consumes no control-plane CPU for error messages. This is the standard Junos way to implement a blackhole route for an unreachable prefix, matching the administrator's intent to drop traffic.
- ✗
next-table
Why it's wrong here
In Junos, the next-table action routes the packet to a different routing table for further lookup; it is commonly used with policies to enforce traffic segregation or route leaking. It does not terminate the packet or drop it, and the lookup may successfully forward the packet. Since the administrator wants to drop the traffic, next-table is inappropriate.
- ✗
resolve
Why it's wrong here
The resolve option on a static route forces Junos to resolve the configured next-hop address through a routing table, allowing an indirect next-hop to be reached via a direct interface. It is a next-hop resolution method, not a forwarding action, so it never causes packets to be dropped. Using resolve would still attempt to forward traffic and is therefore not a drop mechanism.
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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.