JNCIA-Junos logo
Focused certification exam prep
Start practice

JNCIA-Junos Cheat Sheet 2026: One-Page Review of Must-Know Facts

TL;DR
  • JN0-106 has 65 multiple-choice questions, runs 90 minutes, and costs $200 through Pearson VUE.
  • JN0-106 replaced JN0-105 on April 6, 2026 and maps to Junos OS 21.2 - confirm you're studying the right version.
  • No prerequisite is required, and the credential stays valid for three years before recertification.
  • Seven domains matter equally in prep time: don't over-index on routing and skip User Interfaces or Configuration Basics.

Exam Snapshot: The Numbers You Need

Before diving into content review, lock in the mechanics of the exam itself. These are the facts that trip up candidates who studied the technology but never checked the logistics.

DetailValue
Exam codeJN0-106
Administered byPearson VUE (test center or OnVUE online proctoring)
Cost$200 USD
Questions65, multiple-choice
Time limit90 minutes
LanguageEnglish
ResultsPass/fail reported immediately
PrerequisiteNone
Software baseJunos OS 21.2
Validity3 years

JN0-106 replaced the older JN0-105 exam on April 6, 2026, so any study material referencing JN0-105 objectives or an earlier Junos build is outdated. If you want the full breakdown of exam fees, retake costs, and what's bundled with training, the JNCIA-Junos Certification Cost 2026 pricing breakdown covers it in detail. And if you're unsure whether you meet eligibility criteria before registering, check the JNCIA-Junos Requirements guide - spoiler: there isn't a formal prerequisite, but background knowledge still matters.

Version Check: Because JN0-106 is based on Junos OS 21.2, any command syntax, CLI hierarchy, or feature behavior you review should match that release. Study guides written for older exam codes may describe deprecated syntax or missing features.

The Seven Domains, Distilled

Juniper organizes JN0-106 into seven domains. None of them is a throwaway - questions are pulled from all seven, and skipping one because it "feels minor" is a common reason candidates fall short. For a deep dive into each domain's weight and subtopics, see the JNCIA-Junos Exam Domains complete guide to all 7 content areas. This cheat sheet gives you the condensed, exam-morning version.

  1. Networking Fundamentals
  2. Junos OS Fundamentals
  3. User Interfaces
  4. Configuration Basics
  5. Operational Monitoring and Maintenance
  6. Routing Fundamentals
  7. Routing Policy and Firewall Filters

Domain 1: Networking Fundamentals Cheat Notes

Networking Fundamentals

This domain checks whether you understand core networking concepts independent of Junos - the OSI model, addressing, and basic protocol behavior that every device on a network relies on.

  • OSI model layers and what happens at each one
  • IPv4 addressing, subnetting, and CIDR notation
  • Encapsulation and de-encapsulation concepts
  • Basic switching concepts: collision domains, broadcast domains, MAC address learning
  • Basic routing concepts: how a router selects a next hop

If networking theory feels shaky, don't skip straight to Junos commands. A weak grasp of subnetting or the OSI model will cost you points on questions that never mention the word "Junos" at all.

Domain 2: Junos OS Fundamentals Cheat Notes

Junos OS Fundamentals

This is where Junos-specific architecture enters the picture - the software design that separates it from other vendor operating systems.

  • Separation of the control plane and forwarding plane
  • Routing Engine (RE) vs. Packet Forwarding Engine (PFE) roles
  • The single, hierarchical configuration structure shared across platforms
  • Junos releases and how software versioning works
  • High availability concepts: graceful restart, redundant REs on supported platforms

Understanding why Junos uses one unified configuration syntax across routers, switches, and firewalls is a recurring theme - expect questions that test conceptual understanding, not just memorized syntax.

Domain 3: User Interfaces Cheat Notes

User Interfaces

Junos gives you multiple ways to interact with the device. This domain confirms you know when and how to use each one.

  • CLI operational mode vs. configuration mode - what each allows
  • J-Web graphical interface basics
  • CLI navigation: command completion, contextual help (?), pipe (|) filtering
  • Keyboard shortcuts and command history
  • Logging in via console, Telnet, SSH

Key Takeaway

Memorize the difference between operational mode commands (show, ping, traceroute) and configuration mode commands (set, delete, edit). Exam questions often present a CLI prompt and ask what mode you're in or what command would work next.

Domain 4: Configuration Basics Cheat Notes

Configuration Basics

This domain tests your ability to actually build and manage a configuration, not just read one.

  • Candidate configuration vs. active configuration
  • commit, commit confirmed, and rollback behavior
  • set, delete, rename, copy, and insert commands
  • Configuration groups and the apply-groups statement
  • Loading configurations: load merge, load override, load replace
  • Annotating configuration with comments

Candidates frequently underestimate how many questions revolve around commit behavior - especially the safety net that commit confirmed provides if a change locks you out of a device. Know what happens if you don't confirm within the timeout window.

Domain 5: Operational Monitoring and Maintenance Cheat Notes

Operational Monitoring and Maintenance

Once a device is configured, you need to verify it's working and troubleshoot when it isn't.

  • show commands for interfaces, routes, and system status
  • monitor commands for real-time traffic and log viewing
  • System log (syslog) basics and severity levels
  • File system management: storage, cleanup, request commands
  • Software upgrade process fundamentals

This domain rewards hands-on familiarity more than memorization. If you've never actually run show interfaces terse or show route on a live or virtual Junos device, that gap will show up on exam day.

Domain 6: Routing Fundamentals Cheat Notes

Routing Fundamentals

This domain is heavier on protocol knowledge and is often where candidates spend the most study time - for good reason.

  • Static routing configuration and use cases
  • Dynamic routing protocol basics: OSPF, RIP, BGP concepts
  • Routing tables and the forwarding table relationship
  • Route preference (administrative distance equivalent in Junos)
  • Load balancing and equal-cost multipath basics

You don't need to be a BGP expert for JN0-106, but you should know each protocol's basic purpose, how routes are selected, and how Junos decides which route wins when multiple protocols advertise the same destination.

Domain 7: Routing Policy and Firewall Filters Cheat Notes

Routing Policy and Firewall Filters

The final domain covers how traffic is controlled and manipulated as it moves through a Junos device.

  • Routing policy structure: from, then, and term statements
  • Policy application points: import vs. export
  • Firewall filter syntax and match conditions
  • Filter application to interfaces and the difference between input and output filters
  • Default policy behavior when no explicit policy matches

Expect scenario-based questions here: given a policy snippet, what traffic gets permitted, denied, or modified? Practice reading policy terms top-to-bottom, since Junos evaluates them in order and stops at first match.

Command and Mode Quick Reference

Keep this mental map handy while reviewing:

  • Operational mode: show, monitor, ping, traceroute, request, file
  • Configuration mode: set, delete, edit, top, exit, show (configuration view), commit, rollback
  • Moving between modes: configure enters configuration mode; exit or commit-related actions return you to operational mode
  • Committing changes: commit, commit confirmed [minutes], commit check (validates without applying)
  • Undoing changes: rollback 0 through rollback 49 for stored configuration versions
Common Trap: Questions sometimes describe a symptom (a device reverted its configuration on its own) and expect you to recognize commit confirmed timing out without a follow-up commit. This single behavior appears across multiple domains.

The One-Week Countdown Plan

If you've already done your primary studying - ideally following the structured approach in the JNCIA-Junos Study Guide on how to pass on your first attempt - use this final week to consolidate rather than learn new material.

Days 7-6

Networking Fundamentals + Junos OS Fundamentals

  • Re-read OSI layer functions and subnetting math
  • Review control plane/forwarding plane separation
Days 5-4

User Interfaces + Configuration Basics

  • Practice commit, commit confirmed, and rollback sequences on a virtual device
  • Drill CLI mode transitions
Days 3-2

Operational Monitoring + Routing Fundamentals

  • Run and interpret show route, show interfaces terse
  • Review OSPF/RIP/BGP basics and route preference
Day 1

Routing Policy and Firewall Filters + Full Review

Scheduling routing-heavy domains mid-week gives you two extra days to reinforce protocol concepts before the exam, while lighter domains like User Interfaces get reviewed early when retention is easiest to test with flashcards.

Exam-Day Logistics Cheat Sheet

Don't let logistics cost you points you've already earned through study. Confirm these before your appointment:

  • Format choice: decide between an in-person Pearson VUE test center and OnVUE online proctoring - check your ID and workspace requirements in advance if testing from home
  • Timing: 90 minutes for 65 questions gives you roughly 80 seconds per question on average; don't linger on any single item
  • Results: pass/fail is shown immediately after you finish, so you'll know your outcome before leaving the testing session
  • Recertification: the credential is valid for three years; recertify by completing an approved Juniper course such as Introduction to the Junos Operating System or a higher-level course in the same track

Curious whether the exam's difficulty matches its reputation, or how the pass/fail scoring threshold actually works? Read the JNCIA-Junos Exam Difficulty Guide and the JNCIA-Junos Passing Score guide on exactly what you need to pass for specifics beyond what fits on this one-page sheet. If you want context on how JN0-106 compares against historical outcomes, the JNCIA-Junos Pass Rate data breakdown is a useful companion read.

Why This Matters Beyond the Exam: JNCIA-Junos is frequently listed as a baseline credential for network technician and junior network engineer roles at organizations running Juniper gear. If you're weighing whether the investment pays off, the ROI analysis on whether JNCIA-Junos certification is worth it and the JNCIA-Junos Jobs overview break down where this credential actually opens doors.

Frequently Asked Questions

Is this cheat sheet enough to pass JN0-106 on its own?

No. This page is a compact review tool for final-week reinforcement, not a substitute for full study. Pair it with hands-on CLI practice and a complete run-through of all seven domains before your exam date.

Does JN0-106 cover the same material as the retired JN0-105?

JN0-106 replaced JN0-105 on April 6, 2026 and is based on Junos OS 21.2. If you're using older study material, verify it reflects the current exam code and software version before relying on it.

Do I need prior Juniper experience to sit for the exam?

There is no prerequisite certification required for JN0-106. Many candidates still benefit from hands-on lab time or an introductory Junos course before attempting the exam.

Can I take JN0-106 from home?

Yes. In addition to physical Pearson VUE testing centers, the exam is available through OnVUE online proctoring, which lets you test remotely under monitored conditions.

How soon do I find out if I passed?

Pass/fail status is reported immediately after you complete the exam, so you won't have to wait days for a score report.

Keep this page bookmarked as your final-review companion, and revisit the domain-specific breakdown or full study guide whenever you need to go deeper than a one-page summary allows. When you're ready to test your recall under real exam conditions, head to the JNCIA-Junos practice test hub and run a timed simulation before booking your Pearson VUE session.

Ready to pass your JNCIA-Junos exam?

Put this into practice with free JNCIA-Junos questions across every exam domain.