Introduction to the Junos Operating System (IJOS)


Course Overview

This four-day course provides students with the foundational knowledge required to configure, verify, and troubleshoot devices that run Junos OS.

Students will gain a wide variety of practical experience with using the command-line interface (CLI). The course focuses on routers and switches, and explains Layer 3 network interface basics, routing tables, static routes, OSPF, Layer 2 switchports, user accounts, firewall filters, routing policy, and troubleshooting.

Particular attention is given to the power of the candidate configuration, rolling back changes, and the power of the Junos OS configuration hierarchy. The course also discusses the key architectural components of the Junos software, the separation of the control plane and the data plane, and the reasons that Junos OS is built for automation.

Through demonstrations and hands-on labs, students will gain experience in configuring and monitoring Junos OS and monitoring basic device operations. This course is based on Junos OS Release 22.1R1.10.

Who should attend

  • Individuals who work with routers, switches, and firewalls that run Junos OS
  • Individuals who want to learn how to manage Junos OS using the CLI
  • Individuals who want to learn a basic understanding of IPv4, IPv6, routing switching, troubleshooting, packet filtering, and Junos administration concepts


This course is part of the following Certifications:


  • Students are highly recommended to have watched the self-study Getting Started with Networking (e-learning) video series before attending this course.
  • Basic understanding of IPv4 and IPv6.
  • Basic understanding of Ethernet and MAC address learning.
  • Basic understanding of TCP and UDP.
  • Basic understanding of the layered OSI and TCP/IP models.

Course Objectives

After successfully completing this course, you should be able to:

  • Explain the most important benefits of Junos OS and describe the kind of devices that run it.
  • Explain how to remotely connect to the Junos CLI, and how to use operational mode to verify system information.
  • Describe the reasons that IPv6 was created and explain how to read an IPv6 address.
  • Explain the difference between a physical network interface and a logical unit.
  • Demonstrate how the Junos OS CLI can reveal detailed information about network interfaces.
  • Describe how Junos OS stores its configuration using a logical and hierarchical structure.
  • Demonstrate how to deploy configuration in Junos OS, and how the commit process helps to prevent mistakes.
  • Demonstrate the commands and keyboard shortcuts that make Junos CLI configurations more efficient.
  • Describe how routes enter a routing table, and how routers choose the best routes for forwarding traffic.
  • Describe how static routes manually install routing information into a router.
  • Describe how routing protocols can automatically find the best path to remote destinations.
  • Demonstrate how to deploy OSPF to automatically advertise and learn prefixes in a single network.
  • Explain how to manage a switch that runs Junos OS.
  • Explain how to manage a switch that runs Junos OS.
  • Demonstrate how to enable some crucial Junos OS administrative features.
  • Describe the most important things to consider when deploying a new device that runs Junos OS.
  • Demonstrate how knowledge of the underlying Junos OS architecture can bring advantages to network operators.
  • Demonstrate how a knowledge of the underlying Junos OS software helps you when upgrading Junos and troubleshooting networks.
  • Demonstrate the most important and useful tools available in Junos OS that can help you fix real-world problems.
  • Explain how Junos OS can filter and manipulate traffic in real time using stateless firewall filters.
  • Explain how to configure stateless firewall filters that accept or discard packets.
  • Demonstrate some powerful CLI configuration options that can increase your productivity.
  • Describe the advantages and configuration of a variety of different interface types and features.
  • Demonstrate how the architecture of Junos OS is built with automation in mind.
  • Explain how to continue your studies once the course has been completed.

Additional objectives for self-study:

  • Explain how to utilize backup static routes, routing instances, OSPF areas, and BGP.
  • Deploy some of the advanced features available within a firewall filter.
  • Describe advanced troubleshooting and monitoring features available in Junos OS.
  • Demonstrate some advanced device administration features.
  • Describe how routing policies control what prefixes can enter the routing table, and what prefixes can be advertised by protocols.
  • Describe the tasks involved in upgrading Junos OS.
  • Use the J-Web graphical interface to make configuration changes and monitor and maintain Junos devices.
  • Describe the most common network cables in use today, and the reasons for using the Ethernet protocol in modern networks.
  • Describe how IP addresses create end-to-end network communication.
  • Explain how switches enable Layer 2 Ethernet communication between hosts on a shared LAN segment.
  • Describe the difference between TCP and UDP.

Follow On Courses

Course Content

  • Course Introduction
  • SSH and Operational Mode
  • Refresher—IPv6 Addressing
  • Network Interfaces, Part 1—Interface Naming and Logical Units
  • Network Interfaces, Part 2—Revealing and Filtering Detailed Interface Output
  • Reading a Junos OS Configuration
  • Configuring Junos OS—The Basics
  • Configuring Junos OS—Become a Power User
  • Routing Tables, Route Preference, and Longest Prefix Matches
  • Static Routes
  • Dynamic Routing Protocols—The Theory
  • Dynamic Routing Protocols—Configuring OSPF
  • Junos OS Switches, Part 1—VLANs, MAC Tables, and Access Ports
  • Junos OS Switches, Part 2—Trunk Ports
  • Junos OS Device Administration
  • Setting Up a Brand-New Junos OS Device
  • Junos OS Architecture—The Control Plane and the Data Plane
  • Junos OS Architecture—The Software That Powers Junos OS
  • Logging, Troubleshooting, and Monitoring
  • Junos OS Firewall Filters, Part 1—The Theory
  • Junos OS Firewall Filters, Part 2—The Practical
  • Junos OS Configuration—A Deeper Dive
  • Interfaces—A Deeper Dive
  • Junos OS Architecture—APIs and Automation
  • Where Do You Go from Here?
Self-Study Modules
  • Routing—A Deeper Dive
  • Junos OS Firewall Filters—A Deeper Dive
  • Logging, Troubleshooting, and Monitoring—A Deeper Dive
  • Junos OS Device Administration—A Deeper Dive
  • Junos OS Routing Policy
  • Upgrading Junos OS
  • J-Web
  • Refresher—Cables and Ethernet
  • Refresher—IPv4 and Subnetting
  • Refresher—Switches, MAC Learning, Broadcast Domains, and VLANs
  • Refresher—TCP and UDP

Prices & Delivery methods

Online Training

4 days

  • on request
Classroom Training

4 days

  • on request

Subscription duration
365 days

  • on request

Click on town name or "Online Training" to book Schedule



Online Training Time zone: Central European Summer Time (CEST) Course language: German Guaranteed date!
Online Training Time zone: Central European Summer Time (CEST) Course language: German
Online Training Time zone: Central European Summer Time (CEST) Course language: English
Online Training Time zone: Central European Time (CET) Course language: German
Online Training Time zone: Central European Time (CET) Course language: English
Online Training Time zone: Central European Summer Time (CEST) Course language: English


Guaranteed date:   iTLS will carry out all guaranteed training regardless of the number of attendees, exempt from force majeure or other unexpected events, like e.g. accidents or illness of the trainer, which prevent the course from being conducted.
Instructor-led Online Training:   This computer icon in the schedule indicates that this date/time will be conducted as Instructor-Led Online Training.
This is a FLEX course, which is delivered both virtually and in the classroom.