- A
reject
Why wrong: Reject drops traffic but sends ICMP unreachable.
- B
discard
Discard drops traffic silently, no ICMP notification.
- C
next-table
Why wrong: Next-table routes traffic to another routing table, not drop.
- D
resolve
Why wrong: Resolve is used for indirect next-hops, not for dropping traffic.
Question 406 of 514
Discard vs Reject Static Route
This JNCIA-JUNOS practice question tests your understanding of routing fundamentals. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
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?
Quick Answer
The answer is the discard static route option. This is correct because a discard route silently drops all traffic destined for the 10.10.10.0/24 network without generating any ICMP unreachable messages back to the source, whereas a reject route explicitly sends an ICMP destination unreachable notification. On the JNCIA-Junos exam, this distinction between discard vs reject static route is a frequent topic, testing your understanding of how Junos handles unreachable destinations and the impact on network behavior. A common trap is confusing these two options, as both prevent forwarding but differ in their response to the sender. Remember the memory tip: “Discard is dead silent, Reject replies.”
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.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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
Reject drops traffic but sends ICMP unreachable.
- ✓
discard
Why this is correct
Discard drops traffic silently, no ICMP notification.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
next-table
Why it's wrong here
Next-table routes traffic to another routing table, not drop.
- ✗
resolve
Why it's wrong here
Resolve is used for indirect next-hops, not for dropping traffic.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that 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.
Detailed technical explanation
How to think about this question
In Junos, a 'discard' route installs a route with a next-hop type of 'discard' in the forwarding table, causing the packet to be silently dropped at the ingress interface without any ICMP generation. This is commonly used for DDoS mitigation or to blackhole traffic to known malicious destinations. The 'reject' route, by contrast, triggers an ICMP Destination Unreachable (Type 3, Code 0 or 1) response, which can be used for debugging or to inform sources of unreachable networks.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the JNCIA-JUNOS exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Questions learners often ask
What does this JNCIA-JUNOS question test?
Routing Fundamentals — This question tests Routing Fundamentals — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: 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.
What should I do if I get this JNCIA-JUNOS question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jul 4, 2026
This JNCIA-JUNOS 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 JNCIA-JUNOS exam.
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