Introduction to Juniper

The Juniper Introduction series, available on YouTube, is a great way to learn Juniper’s network philosophy.

Many of us are familiar with networking in general, but perhaps we haven’t used Juniper’s platforms before. I learned on Cisco equipment and found it a bit intimidating to move to Juniper.

But it is possible! As long as you have some networking experience, you can use this course to go from never having seen Juniper devices, to becoming a Juniper specialist.

You could even pass the JNCIA Junos exam if you want!

Most videos include optional extras to help you to test your understanding. These include quizzes, labs, study notes, transcripts, and flashcards.

The video series is free to all. The extra content is an inexpensive bonus for Patreon subscribers.

Introduction to SASE (Secure Access Service Edge)

Additional Resources

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Study Notes

CLI Introduction

CLI Introduction  Quiz Page: https://networkdirection.net/labsandquizzes/quizzes/juniper-jncia/cli-introduction Lab Page: https://networkdirection.net/labsandquizzes/labs/jncia-labs/cli-introduction/ Notes All Juniper devices run the Junos operating system. Like any network operating system, this includes a CLI (SSH, Telnet), web interface, and automation options. Junos is based on either FreeBSD, or a customised version of Linux, depending on the Junos version. The Junos CLU has two modes; Operational,...

VLANs and Interfaces

VLANs and Interfaces  Quiz Page: https://networkdirection.net/labsandquizzes/quizzes/juniper-jncia/vlans-and-interfaces Lab Page: https://networkdirection.net/labsandquizzes/labs/jncia-labs/vlans-and-interfaces Notes There are several acronyms for interface types and components: IFD - Interface Physical Device IFL - Interface Logical Device IFF - Address Family IFA - Address Entry Common interface names are: ge - Gigabit ethernet xe - 10G ethernet et - 100G ethernet ae - aggregated...

DHCP

DHCP  Quiz Page: https://networkdirection.net/labsandquizzes/quizzes/juniper-jncia/dhcp Lab Page: https://networkdirection.net/labsandquizzes/labs/jncia-labs/dhcp Notes There are two ways of configuring DHCP; Legacy and extended. Both of these methods are valid. Legacy was created in an older version of Junos, while extended was updated to match across multiple platforms. DHCP requires an active interface in the VLAN that addresses are being sent to...

Active and Candidate

Active and Candidate  Quiz: https://networkdirection.net/labsandquizzes/quizzes/juniper-jncia/active-and-candidate Labs: https://networkdirection.net/labsandquizzes/labs/jncia-labs/active-and-candidate Notes Unlike some vendors, Juniper changes are not applied immediately. They need to be committed first. The 'active' configuration is the configuration that's running right now. The candidate config is a copy of the active that we're making changes to. This overwrites the active configuration when it's committed. Candidate...

Configuration Rollback

Configuration Rollback  Quiz: https://networkdirection.net/labsandquizzes/quizzes/juniper-jncia/configuration-rollback Labs: https://networkdirection.net/labsandquizzes/labs/jncia-labs/configuration-rollback Notes It can sometimes be risky making changes, as mistakes can kick us out of the device. If we use commit confirmed, we can automatically roll back if we don't confirm the changes. Changes are confirmed by running another commit. The default time before rollback is 10 minutes, but this can...

Configuration Groups

Configuration Groups  Quiz: https://networkdirection.net/labsandquizzes/quizzes/juniper-jncia/configuration-groups Labs: https://networkdirection.net/labsandquizzes/labs/jncia-labs/configuration-groups Notes Configuration groups are reusable blocks of configuration that can be applied multiple times. This makes it similar to a template. The contents of a configuration group are just normal configuration items. However, it does support regex, so sometimes it may look different. When a configuration group is applied, it...

Authentication

Authentication  Quiz: https://networkdirection.net/labsandquizzes/quizzes/juniper-jncia/authentication Labs: https://networkdirection.net/labsandquizzes/labs/jncia-labs/authentication Notes Users can be created locally on a Junos device. Each user must have a password set. This may be done with the plain-text-password keyword. This can be misleading. This does not mean the password is stored in plain text. It means that you're about to enter the password in plain text....

A New Device

A New Device   Quiz: https://networkdirection.net/labsandquizzes/quizzes/juniper-jncia/a-new-device Labs: https://networkdirection.net/labsandquizzes/labs/jncia-labs/a-new-device Notes Like most good networking equipment, we can connect a console cable to any Juniper device. This can be a traditional serial console cable or a USB console cable. Sometimes the root password is lost, and needs to be recovered. To do this: Reboot the switch Interrupt boot...

Platforms

Platforms  Notes Juniper's routing platforms: M-Series was the original router (no longer available) T-Series was next, also old now J-Series was the branch router, also old MX series - The current router platform Designed for the edge Virtual (vMX) available ACX - Environmentally hardened routers PTX - High-speed routers 'Packet Transport Routers' Aimed at...

Junos Architecture (Planes)

Junos Architecture (Planes)  Quiz: https://networkdirection.net/labsandquizzes/quizzes/juniper-jncia/architecture-planes Lab: https://networkdirection.net/labsandquizzes/labs/jncia-labs/junos-architecture-planes Notes Network devices logically split their services into two planes; The control plane and the data plane. Traffic going to the device (called exception traffic) is handled by the control plane. This includes routing protocol updates and management traffic. On a Juniper device, the RE (Routing Engine) uses the...

Junos Architecture (Processes)

Junos Architecture (Processes)  Quiz: https://networkdirection.net/labsandquizzes/quizzes/juniper-jncia/architecture-processes Lab: https://networkdirection.net/labsandquizzes/labs/jncia-labs/junos-architecture-processes Notes Operating systems can be classified as modular, or monolithic. Monolithic operating systems have the kernel manage all functions. This is fast, but unfortunately, one area of code can affect another area of code. Modular operating systems split functions into completely separate and independent processes. If there's a fault...

Firewall Filters

Firewall Filters    Quiz: https://networkdirection.net/labsandquizzes/quizzes/juniper-jncia/firewall-filters Lab: https://networkdirection.net/labsandquizzes/labs/jncia-labs/firewall-filters   Notes Firewall filters are the Junos version of an ACL. They are used to match traffic and apply an action. This can be for security (allow or deny traffic), but it can also be for a policy (such as a routing or CoS policy). Generally, firewall filters are...

Routing Table

Routing Table    Quiz: https://networkdirection.net/labsandquizzes/quizzes/juniper-jncia/routing-tables Lab: https://networkdirection.net/labsandquizzes/labs/jncia-labs/routing-table   Notes Junos uses various different routing table for different purposes: inet.0 - IPv4 inet6.0 - IPv6 inet.1 - Multicast forwarding cache inet.2 - Multicast RPF inet.3 - IPv4 MPLS   Routes in the routing table that are marked as active are the ones that are installed into the...

Route Preference

Route Preference    Quiz: https://networkdirection.net/labsandquizzes/quizzes/juniper-jncia/route-preference Lab: https://networkdirection.net/labsandquizzes/labs/jncia-labs/route-preference   Notes Route preference is a value assigned to routing information sources. The more preferred a routing source is, the lower the route preference value is. This is the same thing as 'Administrative Distance', although each vendor uses different values. If a route is learned from two sources (for...

OSPF

OSPF    Quiz: https://networkdirection.net/labsandquizzes/quizzes/juniper-jncia/ospf Lab: https://networkdirection.net/labsandquizzes/labs/jncia-labs/ospf   Notes OSPF configuration is under the Protocols > OSPF hierarchy. Most of the configuration is then under the 'area'. Interfaces added under the area begin to 'participate', meaning that their networks are advertised into OSPF, and they start peering with connected routers. If an interface is configured as passive,...

Routing Policies

Routing Policies    Quiz: https://networkdirection.net/labsandquizzes/quizzes/juniper-jncia/routing-policies Lab: https://networkdirection.net/labsandquizzes/labs/jncia-labs/routing-policies   Notes Routing policies are used to: Manipulate route attributes (the attribute depends on the routing protocol) Decide which routes go into the routing table Decide which routes to advertise to neighbours Redistribute routes   Policies are applied with a routing table centric perspective. Import policies control whether routes...

Routing Instances

Routing Instances    Quiz: https://networkdirection.net/labsandquizzes/quizzes/juniper-jncia/routing-instances Lab: https://networkdirection.net/labsandquizzes/labs/jncia-labs/routing-instances   Notes In the Cisco world, you can use VRF-Lite to create additional routing tables on a router or L3 switch. This creates separation at layer-3 like VLANs do at layer-2. Juniper have something similar (although not identical) called a routing instance. There are several types of routing instance,...

RPMs

RPMs    Quiz: https://networkdirection.net/labsandquizzes/quizzes/juniper-jncia/rpms Lab: https://networkdirection.net/labsandquizzes/labs/jncia-labs/rpms   Notes RPMs (Realtime Performance Monitoring) are like Cisco's SLA's. They are probes that check the availability of an endpoint or its services, or link performance. There can be simple or complicated probes, based on: ICMP HTTP TCP UDP   Performance monitoring can track metrics such as: packet loss response...

Monitoring and Troubleshooting

Monitoring and Troubleshooting    Quiz: https://networkdirection.net/labsandquizzes/quizzes/juniper-jncia/monitoring-and-troubleshooting Lab: https://networkdirection.net/labsandquizzes/labs/jncia-labs/monitoring-and-troubleshooting   Notes Ping and traceroute are popular troubleshooting tools on any device, and Junos is no exception. There are some advanced options available though (see the command summary below). Unlike some other vendors, Juniper rely heavily on log files, rather than just writing to screen. Log files are...