Basic configuration of juniper device

<yambe:breadcrumb>Switch_configuration_notes|Switch configuration</yambe:breadcrumb>

Basic configuration of juniper device

Juniper has very useful beginner tutorials at https://www.juniper.net/dayone in form of "Day One" series. Readers are encouraged to refer to them (esp "Exploring Junos CLI" and "Configuring Junos Basics") so that they are comfortable with material presented in this page.

Basic system configuration

A sample system configuration is:

system {
    host-name VLEAD-EX2200;
    domain-name virtual-labs.ac.in;
    domain-search [ virtual-labs.ac.in iiit.ac.in ];
    location {
        country-code 0091;
        building Nilgiri;
        floor 2;
    }
    root-authentication {
        encrypted-password "<encrypted password>"; ## SECRET-DATA
    }
    name-server {
        10.4.3.222;
    }
    login {
        announcement "Welcome to VLEAD Juniper switch";
        message "Unauthorized access is prohibited";
        user saurabh {
            full-name "Saurabh Barjatiya";
            uid 501;
            class super-user;
            authentication {
                encrypted-password "<encrypted password>"; ## SECRET-DATA
            }
        }                               
    }
    services {
        ssh {
            root-login allow;
        }
        telnet;
        web-management {
            http;
        }
    }
    syslog {
        user * {
            any emergency;
        }
        file messages {
            any notice;
            authorization info;
        }
        file interactive-commands {
            interactive-commands any;
        }
    }
    ntp {
        boot-server time.iiit.ac.in;
        server 10.4.8.3;
    }                             
}

This configuration has following information:

• System host-name, domain-name and search domains
• Switch location
• Root password
• DNS server(s)
• Login announcement and message
• System users with their privilege level and UID
• SSH, telnet and http services are enabled. Root login is enabled over SSH
• Following syslog configuration is achieved
  • Message from any facility of level emergency or above will be sent to all logged in users on their terminals
  • All messages from any facility of level notice or above will be logged to file named messages. Since syslog files are stored in /var/log, file /var/log/messages would receive all these messages.
  • All commands typed interactively (console, SSH) will get stored in file interactive-commands.
• Switch will use ntp-server time.iiit.ac.in at boot to synchronize time and will use ntp server at 10.4.8.3 to regularly synchronize time while running

Creating VLANs

To create an L2 VLAN use:

vlans {
    Management {
        vlan-id 2;
        interface {
            ge-0/0/0.0;
            ge-0/0/1.0;
            ge-0/0/2.0;
            ge-0/0/3.0;                 
        }
    }
}

This would create a L2-VLAN named Management with four member ports.

To give switch an L3 IP address for the VLAN use:

interfaces {
    vlan {
        unit 0 {
            family inet {
                address 10.4.15.5/22;
            }
        }
    }
}
[edit vlans Management]
l3-interface vlan.0;

to create a L3-VLAN named vlan.0 with switch's IP address 10.4.15.5 and to associate this L3-VLAN with Management vlan.

Configure static routes

A sample configuration which uses static routes is:

routing-options {
    static {
        route 0.0.0.0/0 next-hop 10.4.12.1;
        route 192.168.36.0/25 next-hop 10.4.12.1;
    }
}  

Useful commands

A table containing list of useful operational mode juniper commands is:

"Useful operational mode commands"

Command	Description
show system uptime	To see current time and system uptime
configure	Enter configuration mode
configure private	Enter configuration mode where changes done by other users are not visible and similarly changes done are not visible to other users
configure exclusive	Enter configuration mode so that only current user can configure the device to avoid race conditions among various administrators
file list, file show, file copy	Work with various files from cli. A simpler way could be to ssh to device and use shell
telnet, ssh, ping, traceroute	Use telnet, ssh, ping or traceroute clients
start shell	Start a shell inside cli
monitor start messages	To display messages sent to messages file on console.
monitor list	Obtain ist of channels being monitored
monitor stop messages	To stop monitoring messages file on console
show host	Resolve hostname to IP address using configured DNS
set date	Set system date and time manually or using ntp
show ntp {associations, status}	To see ntp association or status information
show chasis hardware	See information about various slots, PICs and ports available on current switch
show log messages	To see messages log channel
last 30	To see last 30 messages sent to messages channel
show system connections	Show current network connection status, similar to netstat

A table containing list of useful configuration mode juniper commands is:

"Useful configuration mode commands"

Command	Description
annotate	Leave comments about a configuration statement
show	See current candidate configuration
compare	Compare candidate configuration with running configuration (ie rollback 0 configuration)
display set	Display current configuration in terms of set commands
display detail	Display more detailed information about configuration
display xml	Show configuration in XML format
commit	Commit candidate configuration as running configuration
commit at	Commit candidate configuration as running configuration at given time
commit confirmed	Commit configuration and wait for confirmation within next specified number of minutes. If the new configuration is not confirmed thorough another 'commit' command the automatically rollback to previous configuration when time is over
commit check	Check configuration through various commit scripts and tests to verify whether it passes various commit checks
edit, set, delete, rename, copy, activate, deactivate	Change various configuration values
rollback	Restore previous configuration using number. Up to last 49 configuration can be restored using rollback
run	Run operational mode command from configuration mode
top, up, exit	Move around while editing configuration

Miscellaneous issues

Using out-of-band management interface on EX series switches

EX series switches come with out of band management interface which can be used using:

set interfaces me0 unit 0 family inet address 172.26.27.44/24

Note for various other devices management interface is called fxp0

Configure host for syslog

To send syslog messages to a host instead of regular file or user console use:

set system syslog host loghost any notice

In such cases special prefix can be attached to log messages to indicate that they originated from current device using:

set system syslog host loghost log-prefix JUNOS

Further messages can be configured to have facility and level information using:

set explicit-priority

configuration option when within [edit system syslog host] or [edit system syslog file]

Finally to send messages with custom facility name to help with separation of logs from multiple devices on log server use:

set facility-override local7