JunOS Basics

In this Tutorial We will be discussing about the basic of the JunOS which will include:

• How to setup the root password
• How to change the device name
• How to create a user with admin right using a password and using a SSH key
• How to setup the management interface to ssh in to the switch
• How to create VLAN's
• How to create access and trunk ports
• How to create interfaces range
• How to connect 2 switches

Prerequisites

To complete this tutorial, you will need:

• A laptop running Linux or MacOS. for this tutorial I will be using a laptop running Ubuntu 16
• A console cable. Since all the new laptops today don't come with a USB port, you will need a USB to Console adapter
• The program "Screen"

If you don't have "screen" install it with the command below

sudo apt-get install screen

Accessing the device

• Step 1: Plug the console cable to you device into the console port and start screen as root user on your laptop

screen /dev/ttyUSB0

• step 2: Power on your device

After the device finished booting you will get at the prompt below

• Step 3: Enter the username and password

By default, all Juniper devices username is "root" with no password. At the prompt, just type in root and hit enter

How to setup the root password

When you come from a CISCO world like me, at the beginning it is a little bit confusing when working with JunOS. But, with time running a couple of commands, you get use to the concept.

For us to setup the root password, we need to be in configuration mode (#). Right now our prompt is showing "%". tyoe in

cli

to and the prompt will change to ">" which is the operational mode and after that type in "edit" or "configuration" to enter the configuration mode

root@switch:RE:0% cli
{master:0}
root@switch> edit 
Entering configuration mode
{master:0}[edit]
root@switch#

To setup the root password with a plain-text password the command it "set system root-authentication plain-text-password" Type the command and hit enter. You will be asked to enter a password twice.

root@switch# set system root-authentication plain-text-password    
New password:
Retype new password:
{master:0}[edit]
root@switch#

Note: just setting up the password is not enough, you need to save the change that you just made. In JunOS the way to save changes is by typing the command "commit".

But before we save the changes, there is another usefully command that allows us to see what are all the changes made to the device before we save the changes and that command is "show | compare"

root@switch# show | compare 
[edit system]
+   root-authentication {
+       encrypted-password "$1$vVYnP0uH$YmTKnA.L0W0KGFtTw36NJ/"; ## SECRET-DATA
+   }

The + sign in front of each lines means that those lines will add to our devices configuration. Note: you can make all you changes and when done you can type the command " show | compare" before you save with "commit" or you can do one change at the time and do "show | compare" and "commit" and go to the next change. I recommend if you are starting to just do one change and "show | compare" then "commit"

Now we can save our first configuration

root@switch# commit 
configuration check succeeds
commit complete
{master:0}[edit]
root@switch#

Now that we have the root password set, we are going to give a switch a name: we are going to use "asw-a1-dfw" as name

How to change the device name

The command to setup the device name is :set system host-name "device_name"

{master:0}[edit]
root@switch# set system host-name asw-a1-dfw 

Do a "show | compare"

 root@switch# show | compare 
[edit system]
+  host-name asw-a1-dfw;

Then a "commit"

root@switch# commit 
configuration check succeeds
commit complete
{master:0}[edit]
root@asw-a1-dfw# 

We can see that the device changed name from "switch" to "asw-a1-dfw"

How to create a privileged user

In the session, we are gong to setup 2 users. One user with a password and another user with a SSH key. The user with the password will be called ppaul1 and the user with the SSH key will be called ppaul2.