JunOS Basics

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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

Login1.png

  • 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

Login.png

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 "%". type in 

cli

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 is "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 useful command that allows us to see what are all the changes made to the device before we scan ave 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 to added 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 the switch a name: we are going to use "asw-a1-dfw" as name Note: in a production environment I recommend to disable login with root password. We will discuss about this later.

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.

Setting user with password

Create user ppaul1 

root@asw-a1-dfw# set system login user ppaul1 class super-user authentication plain-text-password
New password:
Retype new password:

 root@asw-a1-dfw# show | compare 
[edit system]
+   login {
+       user ppaul1 {
+           class super-user;
+           authentication {
+               encrypted-password "$1$LivXhitM$r9CHQgnCiT6nzRt7XhM/k/"; ## SECRET-DATA
+           }
+       }
+   }

 root@asw-a1-dfw# commit 
configuration check succeeds
commit complete


Testing user ppaul1

logout from the user "root" by just typing "exit" until you get to the login prompt 

login: ppaul1
Password:
--- JUNOS 10.4R1.9 built 2010-12-04 09:57:12 UTC
{master:0}
ppaul1@asw-a1-dfw>

We can see now that we have login as the user "ppaul1" with a password.in the next step we will create the user ppaul2 with SSH key.

Setting user with SSH key

You can login as root to create the user "ppaul2 or just use the user "ppaul1" to create the user "ppaul2" since ppaul2 is a supe-user 

ppaul1@asw-a1-dfw# set system login user ppaul2 class super-user authentication ssh-rsa "ssh-rsa    AAAAB3NzaC1yc2EAAAADAQABAAABAQDST4EbXJc9l/AdrVmOZEPl3sxi6qjGIZyPwkupthSdooFHxPxUIh/a5PC9bMk5go6KvRoChpc4L8XuMRsxLTd6Ro6DsWIZieGHFuO/AL9SRUtmevGiSC2q4ibR7ACosJBUvKPRVK8anYnMSL9YWd7lnmVLnW5mvOM3Alhd8aTNKE3/H9ogDt9UfndEJXmieMTLJzGvx65sw6riqa5hh6iOcw02qb3QQCKLSRJmUJQuToY4oo/ZdLl/prEDKQ0I9DSnOxRYIvZxvUsTzwoXVq9X9dWGkKAAMDw7f2DJfa/4uCNT2dKPydApeN0ea2/69VRL3fmTz47y0CC1RTEd8j1j U18pc"

 ppaul1@asw-a1-dfw# show | compare 
[edit system login]
+    user ppaul2 {
+        class super-user;
+        authentication {
+            ssh-rsa "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDST4EbXJc9l/AdrVmOZEPl3sxi6qjGIZyPwkupthSdooFHxPxUIh/a5PC9bMk5go6KvRoChpc4L8XuMRsxLTd6Ro6DsWIZieGHFuO /AL9SRUtmevGiSC2q4ibR7ACosJBUvKPRVK8anYnMSL9YWd7lnmVLnW5mvOM3Alhd8aTNKE3/H9ogDt9UfndEJXmieMTLJzGvx65sw6riqa5hh6iOcw02qb3QQCKLSRJmUJQuToY4oo/ZdLl/prEDKQ0I9DSnOxRYIvZxvUsTzwoXVq9X9dWGkKAAMDw7f2DJfa/4uCNT2dKPydApeN0ea2/69VRL3fmTz47y0CC1RTEd8j1j U18pc"; ## SECRET-DATA
+        }
+    }

ppaul1@asw-a1-dfw# commit 
configuration check succeeds
commit complete

we can not test yet the user ppaul2 until we setup the management interface and ssh on the device which we are going to do in the next session (see 6.3)

How to setup management interface and SSH

Setting up mamagement interface

The management interface on Juniper switch is called "me0" Also all interfaces are enable by default on Juniper switches. Let use the command "show interfaces me0" to see its output.

Note you need to be in the operational mode (>) to execute this command 

 ppaul1@asw-a1-dfw> show interfaces me0    
Physical interface: me0, Enabled, Physical link is Down
  Interface index: 1, SNMP ifIndex: 33
  Type: Ethernet, Link-level type: Ethernet, MTU: 1514
  Device flags   : Present Running No-Carrier
  Interface flags: Hardware-Down SNMP-Traps
  Current address: 5c:5e:ab:75:6c:81, Hardware address: 5c:5e:ab:75:6c:ff
  Last flapped   : 2016-07-25 01:49:33 UTC (00:00:06 ago)
    Input packets : 1248 
    Output packets: 280
  Logical interface me0.0 (Index 6) (SNMP ifIndex 34) 
    Flags: Device-Down SNMP-Traps Encapsulation: ENET2
    Input packets : 1248 
    Output packets: 280
    Protocol eth-switch
      Flags: Is-Primary

We can see that interface is enable and down. Down means there is no cable plugged to it. Now in enter configuration mode and type " show interface me0" 

 {master:0}[edit]
ppaul1@asw-a1-dfw# show interfaces me0 
{master:0}[edit]
ppaul1@asw-a1-dfw# set interfaces

We see that we have no output, this means that true the interface is enable but it is not configured

Let us configure the interface by typing the command " set interfaces me0 unit 0 family inet address 10.192.0.100/24.(Please change this IP address to match your environment) 

ppaul1@asw-a1-dfw# set interfaces me0 unite 0 family inet address 10.192.0.101/24

See what will be the changes 

 {master:0}[edit]
ppaul1@asw-a1-dfw# show | compare 
[edit interfaces]
+   me0 {
+       unit 0 {
+           family inet {
+               address 10.192.0.101/24;
+           }
+       }
+   }

Now save the changes 

 ppaul1@asw-a1-dfw# commit 
configuration check succeeds
commit complete

check again the interface 

ppaul1@asw-a1-dfw# show interfaces me0 
unit 0 {
    family inet {
        address 10.192.0.101/24;
    }
}

we see that now we have an ip address set for on the interface

Next step it to plug a cable to the interface and check the link on the interface to see if the link is "up". get back in operational mode and type "show interfaces me0" or form the configuration mode you can just type "run show interfaces me0" 

 ppaul1@asw-a1-dfw# run show interfaces me0 
Physical interface: me0, Enabled, Physical link is Up
  Interface index: 1, SNMP ifIndex: 33
  Type: Ethernet, Link-level type: Ethernet, MTU: 1514, Speed: 1000mbps
  Device flags   : Present Running
  Interface flags: SNMP-Traps
  Link type      : Full-Duplex
  Current address: 5c:5e:ab:75:6c:ff, Hardware address: 5c:5e:ab:75:6c:ff
  Last flapped   : 2016-07-25 02:05:21 UTC (00:00:44 ago)
    Input packets : 1248 
    Output packets: 283
  Logical interface me0.0 (Index 7) (SNMP ifIndex 34) 
    Flags: SNMP-Traps Encapsulation: ENET2
    Bandwidth: 0
    Input packets : 0 
    Output packets: 3
    Protocol inet
      Flags: Is-Primary
      Addresses, Flags: Is-Default Is-Preferred Is-Primary
        Destination: 10.192.0/24, Local: 10.192.0.101, Broadcast: 10.192.0.255

We see from the output that the interface is up .The next step will be to setup enable SSH

Enable SSH

We just need one simple command to enable SSH on the device. The command is "set system services ssh" 

ppaul1@asw-a1-dfw# set system services ssh

ppaul1@asw-a1-dfw# show | compare
[edit system]
+   services {
+       ssh;
+   }

{master:0}[edit]
ppaul1@asw-a1-dfw# commit 
configuration check succeedscommit complete

Now let us test user "ppaul2" . on your laptop open a terminal window and type in "ssh ppaul2@10.192.0.101" (Change IP address with your IP address you setup)

Testing user ppaul2

ssh ppaul2@10.192.0.101
--- JUNOS 10.4R1.9 built 2010-12-04 09:57:12 UTC
{master:0}
ppaul2@asw-a1-dfw>

We are able to login to the device with user "ppaul2: without a password. In the next session we are going to create 4 VLANs.

How to create VLANs

In this session we are going to create 4 VLAN's

  • Vlan private1-a-dfw with ID 2000
  • Vlan private1-b-dfw with ID 2001
  • Vlan private1-c-dfw with ID 2002
  • Vlan private1-d-dfw with ID 2003

The command to create the VLAN's is " set vlans vlan_name vlan-id XXXX" 

ppaul2@asw-a1-dfw# set vlans private1-a-dfw vlan-id 2000

Check the output before saving 

ppaul2@asw-a1-dfw# show | compare 
[edit]
+  vlans {
+      private1-a-dfw {
+          vlan-id 2000;
+      }
+  }

ppaul2@asw-a1-dfw# commit 
configuration check succeedscommit complete

We have the first VLAN, we are going to use the same command the create the other VLAN's by changing the vlan_name and the the vlan_id. After create all the VLAN's type the command "show vlans"

Output 

ppaul2@asw-a1-dfw# show vlans 
private1-a-dfw {
    vlan-id 2000;
}
private1-b-dfw {
    vlan-id 2001;
}
private1-c-dfw {
    vlan-id 2002;
}
private1-d-dfw {
    vlan-id 2003;
}

Now we have all the VLAN's setup, in the next session we are going to create 5 interfaces-range.

How to create interfaces range

As I mentioned earlier when setting up the management interface me0, all interfaces on the Juniper devices are enable by default. Setting up interfaces range, will help better organized and manage the device. Think of interface range as a group or category in which you can group interfaces with the same configuration set. We mentioned earlier that by default all interfaces on the Juniper devices are enable. For security reason, it is best to disable all interfaces by default and just enable it when it has to be used.

The first interface-range we are going to create is the interface-range called disable and will have ford description DISABLED and we will set the interface to disable. 

ppaul2@asw-a1-dfw# set interfaces interface-range disable disable description DISABLED 

{master:0}[edit]
ppaul2@asw-a1-dfw# show | compare 
[edit interfaces]
+   interface-range disable {
+       description DISABLED;
+       disable;
+   }

we can see that we create an interface-range name disable with a description DISABLE and we disable the interface range.

we can not save the changes we made until we interface range has a member. if we try to save the change right now with the interface-range having a member will we get: 

ppaul2@asw-a1-dfw# commit 
error: interface-range 'disable' has no member/member-range statements
error: interface-ranges expansion failed
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