Monthly Archives: April 2023

38. Factory-default Configuration Let’s talk about the factory default configuration found on a Junos device. All platforms running Junos are shipped with a factory default configuration. So when you have a brand new Junos device, it is going to be running a factory default configuration. All factory default configurations allow access using the route account. […]

35. Junos Configuration Files Let’s talk about Junos configuration files. So in this video, we’ll talk about some of the file operations that we can perform, or in other words, we’ll look at some of the file commands that are available on a Junos device. So on a Junos device, we can use the command, […]

32. Configuration Hierarchy Let’s talk about the Junos configuration hierarchy. When we configured the Junos device, we have two options. We can choose to configure it from the top of the configuration hierarchy, which is the edit hierarchy at the top. Or we can choose to navigate into an item specific configuration hierarchy and configure […]

29. Active vs Candidate Configuration Let’s talk about an interesting concept called active configuration and candidate configuration. So, the configuration that is currently active on the Junos device is what is called as the active configuration. Some vendors also call this as running configuration. This is also the configuration that is loaded on a device […]

26. CLI Help Let’s talk about the help commands available on a Junos device primarily. There are three help commands. The first one is help topic. This shows you usage guidelines for a specific statement. Then we have help reference. This will show you summarized information about a specific statement. And third, we have helped […]

23. CLI Functionality Let’s start by talking about the Junos alive functionality. There’s a couple of ways by which you can access the Junos CLI. The first method is called out-of-band, and this uses the serial console port or a dedicated management port to connect with the device. A connection like this does not use […]

16. Class of Service Let’s talk about class of service. When you forward packets on a network, the devices that are responsible for forwarding the packets such as routers and firewalls, they forward the packets independently meaning without applying any special treatment to those packets. Most of the time this is not a problem. So, […]

19. Junos Software Architecture Let’s talk about the Junos software architecture. The Junos kernel is based on the FreeBSD Unix operating system, which is an open-source software. So, the Junos kernel or, in other words, the core of the Junos operating system is based on FreeBSD Unix operating system. The Junos functionality is compartmentalized into […]

13. Subnetting Example 4 All right, let’s look at one more example of subnetting, and this time again, we’re going to change it a bit. The question is which subnet does 200.1.1.10/29 belong to? In the examples that we looked at earlier, we were given an IP address and we had to break it down […]

10. Subnetting Example 1 It’s now time to do some subnetting. Make sure you have a pen and a paper handy as we’ll be doing some live examples. Subnetting is the process of taking a large network and breaking it down into smaller networks, also known as subnets. Let’s first understand the steps for subnetting. […]