Juniper JunOS Command Overview and Howtos Switch, Router, Firewall Tutorial Guide

How Do You Apply Changes You've Made?

You can make all kinds of changes to the switch, but remember they are not actually active until you run the "commit" command. This means adding or deleting config options will not have any effect until you run "commit".

Under configure mode:

root# commit commit complete

How To Set The Hostname:

set system host-name realtechtalk.com

Then commit the changes and the shell will now have your hostname.

Reboot:

request system reboot
Reboot the system ? [yes,no] (no) yes

Shutdown NOW!
[pid 59765]

How Can You Get Info About the Hardware /model/serial number?

In CLI mode:

show chassis hardware

Set Default Config:

load factory-default warning: activating factory configuration

#if you already have DHCP on the network, I recommend deleting the DHCP service which may start handing out IPs by default

delete system services dhcp

#in most firmware you'll need to set a root password before you can commit

DHCP Server/Pool Creation

This creates a DHCP Pool for the 20.1.20.0 subnet, however it does nothing unless you actually have an interface assigned with an iP from that subnet.

set system services dhcp pool 20.1.20.0/24

Restrict IP range that is given out

Let's say we want to reserve 20.1.20.200 and up for static IPs we can do this:

set system services dhcp pool 20.1.20.0/24 address-range low 20.1.20.200 high 20.1.20.254

We still probably want things like gateway and DNS for our DHCP:

Here we use evil Google's free but tapped 8.8.8.8 nameserver as an example (run the command again to add more DNS servers).

set system services dhcp pool 20.1.20.0/24 name-server 8.8.8.8

Set DHCP Gateway to be 20.1.20.1

set system services dhcp pool 20.1.20.0/24 router 20.1.20.1

Check DHCP Binding/Client info:

In CLI mode:

show system services dhcp binding

It should show a list of fields like this:

IP address       Hardware address   Type     Lease expires at

Setting IPs

If it's not the case you can set DHCP client for vlan 0 or whatever VLAN like this:

set interfaces vlan.0 family inet dhcp

If using a static IP you can set a static route for default gateway like this:

This assumes your default gateway is 192.168.1.1

set routing-options static route 0.0.0.0 next-hop 192.168.1.1

Find the IP

By default most JunOS devices will try to get a DHCP address from the network on vlan 0.

In CLI mode type this:

show interfaces vlan.0

Set Root Password

root# set system root-authentication plain-text-password New password: Retype new password:

Enable SSH access:

In conf mode:

set system services ssh

SSH to the device doesn't work as root by default, you should create a separate user. It doesn't allow the user to attempt password authentication.

Received disconnect from 192.168.1.205 port 22:2: Too many authentication failures for root Disconnected from 192.168.1.205 port 22

The error above could be caused by this problem described here, where you will need to ensure that password auth is preferred before trying to use client side keys.

If it still doesn't work, you may need to manually recreate the server rsa and dsa keys

ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key

ssh-keygen -t dsa -f /etc/ssh/ssh_host_dsa_key

This will fix the root access by password (which should only be done for testing/non-production!)

set system services ssh root-login allow

How To Disable STP (RSTP):

RSTP is normally enabled by default to avoid loops, however, if the switch may be connected to other uplinks that will disable the port for sending BPDU packets, it may be wise to disable RSTP in this circumstance in conf mode:

delete protocols rstp

See what protocols are enabled on the switch:

show protocols

protocols {
    igmp-snooping {
        vlan all;
    }
    rstp;
    lldp {
        interface all;
    }
    lldp-med {
        interface all;
    }
}

How To Check Logs:

In cli mode:

show log ?

Name of log file authd_libstats Size: 0, Last changed: Nov 17 21:43:30 authd_profilelib Size: 0, Last changed: Nov 17 21:43:30 authd_sdb.log Size: 0, Last changed: Nov 17 21:43:30 chassisd Size: 350470, Last changed: Nov 18 01:06:32 cosd Size: 64148, Last changed: Nov 17 22:00:19 dcd Size: 339433, Last changed: Nov 18 01:42:56 default-log-messages Size: 0, Last changed: Nov 18 01:14:51 dfwc Size: 0, Last changed: Nov 17 21:43:14 dhcp_logfile Size: 60198, Last changed: Nov 18 01:43:03 dhcp_logfile.0.gz Size: 8135, Last changed: Nov 18 01:35:31 dhcp_logfile.1.gz Size: 7401, Last changed: Nov 18 01:18:27 eccd Size: 0, Last changed: Nov 17 21:43:12 erp-default Size: 100197, Last changed: Nov 18 01:41:26 ext/ Last changed: Nov 17 21:40:09 flowc/ Last changed: Nov 17 21:40:09 ggsn/ Last changed: Nov 17 21:40:09 gres-tp Size: 8193, Last changed: Nov 17 22:00:19 interactive-commands Size: 48350, Last changed: Nov 18 01:43:03 interactive-commands.0.gz Size: 9672, Last changed: Nov 17 22:30:01 inventory Size: 5266, Last changed: Nov 18 01:05:53 license Size: 0, Last changed: Nov 17 21:44:44 license_subs_trace.log Size: 4354, Last changed: Nov 17 22:01:21 mastership Size: 1014, Last changed: Nov 17 22:00:19 messages Size: 23596, Last changed: Nov 18 01:41:31 messages.0.gz Size: 24441, Last changed: Nov 17 22:00:00 messages.1.gz Size: 22618, Last changed: Nov 17 22:00:00 pgmd Size: 336, Last changed: Nov 17 21:59:04 snapshot Size: 2926, Last changed: Nov 17 21:59:40 user Show recent user logins wtmp Size: 20772, Last changed: Nov 17 22:11:52 wtmp.0.gz Size: 96, Last changed: Nov 17 21:44:46

show log messages

Work with a range:

With Juniper you need to create a "range" membership list first.

For example below you can use a wildcard on ge-0/0/* or even ge-*/*/* or even ge-0/0/[0-15] etc..

set interfaces interface-range rttall member-range ge-0/0/0 to ge-0/0/15

set interfaces interface-range rttall member ge-0/0/*

Examples of working with the range:

delete interfaces interface-range rtt unit 0

set interfaces interface-range rttall unit 0 family bridge

Backup Firmware:

root@t1test> request system snapshot media internal error: Cannot snapshot to current boot device

If you just want the factory firmware/settings backed up:

request system snapshot factory slice alternate

If you get that error just put the snapshot on the alternative partition in this case /dev/da0s2a

root@t1test> request system snapshot slice alternate

Formatting alternate root (/dev/da0s2a)... Copying '/dev/da0s1a' to '/dev/da0s2a' .. (this may take a few minutes) The following filesystems were archived: /

Mount the backup like this:

mkdir /var/mtp/da0s2a

mount -t ufs /dev/da0s2a /var/tmp/da0s2a/

Check Resource Usage (eg. CPU utilization and RAM utilization)

show chassis routing-engine
Routing Engine status: Slot 0: Current state Master DRAM 512 Memory utilization 55 percent CPU utilization: User 2 percent Background 0 percent Kernel 4 percent Interrupt 0 percent Idle 94 percent Model EX2200-C-12P-2G, POE Serial ID GR0215260031 Start time 2014-03-13 10:12:08 UTC Uptime 13 days, 15 hours, 55 minutes, 38 seconds Last reboot reason Router rebooted after a normal shutdown. Load averages: 1 minute 5 minute 15 minute 0.00 0.06 0.05

Why does my Juniper JunOS Switch/Router/Firewall Showing High Ping?

You may ping the Juniper device and find even a device on the same physical switch will have higher ping.

Eg. Server 1 on Switch 1 will show ping like this:

64 bytes from 10.20.5.2: icmp_seq=1 ttl=64 time=1.93 ms 64 bytes from 10.20.5.2: icmp_seq=2 ttl=64 time=1.89 ms 64 bytes from 10.20.5.2: icmp_seq=3 ttl=64 time=1.91 ms 64 bytes from 10.20.5.2: icmp_seq=4 ttl=64 time=1.87 ms 64 bytes from 10.20.5.2: icmp_seq=5 ttl=64 time=1.91 ms

But pinging a server on the same switch shows ping like this:

64 bytes from 10.20.5.21: icmp_seq=1 ttl=64 time=0.362 ms
64 bytes from 10.20.5.21: icmp_seq=2 ttl=64 time=0.371 ms
64 bytes from 10.20.5.21: icmp_seq=3 ttl=64 time=0.388 ms
64 bytes from 10.20.5.21: icmp_seq=4 ttl=64 time=0.371 ms

The reason is just because of how JunOS prioritizes ICMP to the RE (Routing Engine) and is normal and does not indicate any impairment to performance. See here: https://supportportal.juniper.net/s/article/Junos-OS-ICMP-Ping-Showing-Latency-for-Host-Inbound-and-Outbound-traffic?language=en_US

Check Firmware/Software Version

show system software detail

Information for jbase: Comment: JUNOS Base OS Software Suite [12.3R6.6]

Check Temperature (in CLI mode)

show chassis environment
Class Item Status Measurement Power FPC 0 Power Supply 0 OK Temp FPC 0 GEPHY1 OK 50 degrees C / 122 degrees F FPC 0 GEPHY2 OK 50 degrees C / 122 degrees F FPC 0 GEPHY3 OK 50 degrees C / 122 degrees F FPC 0 GEPHY4 OK 45 degrees C / 113 degrees F

Change SSH Timeout time:

The default is just 1800 seconds, which means after 30 minutes you will be kicked out of SSH. Let's say you wanto to stay logged in for much longer. Conversely, you can also set it to be much lower.

You an also set "never" as the timeout time.

You just use this command to set the time in seconds for time out.

set applications application junos-ssh inactivity-timeout 4294967295

The number above is the highest value you can set which works out to be about 49710 days!

Show MAC Addresses:

These commands are done from "cli" mode.

show ethernet-switching table brief

On a firewall you would use this to show mac addresses:

show bridge mac-table 
MAC flags (S -static MAC, D -dynamic MAC, L -locally learned
           SE -Statistics enabled, NM -Non configured MAC, R -Remote PE MAC)

Routing instance : default-switch
 Bridging domain : rtt138, VLAN : 5
   MAC                 MAC      Logical
   address             flags    interface
   00:24:2c:00:ef:01   D        ge-0/0/1.0

Check system snapshot

show system snapshot media internal Information for snapshot on internal (/dev/da0s1a) (primary) Creation date: Sep 30 18:41:52 2021 JUNOS version on snapshot: junos : 12.1X46-D77.1-domestic Information for snapshot on internal (/dev/da0s2a) (backup) Creation date: Sep 30 22:08:07 2021 JUNOS version on snapshot: junos : 12.1X46-D77.1-domestic

Upgrade Firwmare:

request system software add no-copy /var/tmp/junos-srxsme-15-domestic.tgz

#apply the update by rebooting

request system reboot

How To Set Which Devices can physically use a port

Say you don't want someone plugging in another device to their port, maybe the port the user is plugged into is the company workstation and only the MAC of that workstation should be allowed to use the port. Or maybe it's a VOIP phone and only the MAC of that VOIP phone should have access.

You can use the mac "source-address-filter" option:

edit interfaces ge-0/0/0 set gigether-options source-address-filter ge-0/0/0 { gigether-options { source-address-filter { 00:21:1e:00:ae:11; } }In the option above we set the interface ge-0/0/0 to only allow the device with MAC "00:21:1e:00:ae:11" to use the port. You could also add more than one MAC address if there are multiple MACs that would be allowed to use the port.

VLAN Stuff

How to Create a VLAN:

In this example we create a vlan called "rttvlan" with an id of "101"

set vlans rttvlan vlan-id 101

Assign the VLAN called "rttvlan" to port 0

set interfaces ge-0/0/0 unit 0 family ethernet-switching vlan members rttvlan

In this example we assume you have a VLAN ID of 101 and you want to assign it an IP.

If you wanted it to get a DHCP

set interfaces vlan unit 101 family inet dhcp

Or Static

set interfaces vlan unit 101 family inet address 10.10.10.200/24

Now we need to assign an l3 interface to the vlan 101 or it won't work.

set vlans lan l3-interface vlan.101

Set Transparent Mode on Juniper SRX Firewall:

set interfaces interface-range ge0/0/[0-15] unit 0 family bridge

[edit interfaces ge-0/0/12 unit 0 family]
'bridge'
    family bridge and rest of the families are mutually exclusive
[edit interfaces ge-0/0/13 unit 0 family]
'bridge'
    family bridge and rest of the families are mutually exclusive
[edit interfaces ge-0/0/14 unit 0 family]
'bridge'
    family bridge and rest of the families are mutually exclusive
[edit interfaces ge-0/0/15 unit 0 family]
'bridge'
    family bridge and rest of the families are mutually exclusive
error: commit failed: (statements constraint check failed)

delete interfaces ge-0/0/0 delete interfaces ge-0/0/1 delete interfaces ge-0/0/2 delete interfaces ge-0/0/3 delete interfaces ge-0/0/4 delete interfaces ge-0/0/5 delete interfaces ge-0/0/6 delete interfaces ge-0/0/7 delete interfaces ge-0/0/8 delete interfaces ge-0/0/9 delete interfaces ge-0/0/10 delete interfaces ge-0/0/11 delete interfaces ge-0/0/12 delete interfaces ge-0/0/13 delete interfaces ge-0/0/14 delete interfaces ge-0/0/15

#after this the interfaces will not be shown under "show"

#delete vlans and all security or it will break things when we try to enable bridging/we have interfaces that are assgined to vlans that no longer exist

delete vlans

delete interfaces vlan

delete security

#now we enable transparent mode by setting the interfaces as family type bridge, we create a vlan for them and associate them with an irb for layer 3 routing

#for now we just add port 0 and 1 to vlan 5 and make those ports transparent

set interfaces ge-0/0/0 unit 0 family bridge interface-mode access vlan-id 5

set interfaces ge-0/0/1 unit 0 family bridge interface-mode access vlan-id 5

#now we have to assign the relevant interfaces to our security zone and allow our security zone to talk to itself (otherwise nothing works as in you can't DHCP from your LAN, you can't ping out or do anything

#in this mode we will be leaving everything open, this is a good way to analyze traffic and slowly restrict unnecessary services and applications for security reasons

#notice we use the same vlan we assigned to ge0/0/0 and ge0/0/1 we also made irb.1 as the interface which we'll have to configure next

set bridge-domains rtt138 domain-type bridge vlan-id 5 routing-interface irb.1

#set the IP on your IRB interface to 10.25.20.200 (change to what suits you)

set interfaces irb unit 1 family inet address 10.25.20.200/24

#after committing and to actually enable transparent mode you must reboot

root# commit warning: Interfaces are changed from route mode to transparent mode. Please reboot the device or all nodes in the HA cluster! commit complete

Juniper SRX failure to update firmware:

This normally happens if you go from old firmware on a unit that you have never used. For example JunOS 10, you should upgrade to the latest version of 10, then go to 11, and then go to version 12 etc..

root> ... add no-copy /cf/var/junos-srxsme-12.3X48-D75.4-domestic.tgz NOTICE: Validating configuration against junos-srxsme-12.3X48-D75.4-domestic.tgz. NOTICE: Use the 'no-validate' option to skip this if desired. Formatting alternate root (/dev/da0s2a)... /dev/da0s2a: 298.0MB (610284 sectors) block size 16384, fragment size 2048 using 4 cylinder groups of 74.50MB, 4768 blks, 9600 inodes. super-block backups (for fsck -b #) at: 32, 152608, 305184, 457760 ** /dev/altroot FILE SYSTEM CLEAN; SKIPPING CHECKS clean, 150096 free (24 frags, 18759 blocks, 0.0% fragmentation) Checking compatibility with configuration Initializing... Verified manifest signed by PackageProduction_10_0_0 Verified junos-10.0R3.10-domestic signed by PackageProduction_10_0_0 Using junos-12.3X48-D75.4-domestic from /altroot/cf/packages/install-tmp/junos-12.3X48-D75.4-domestic Copying package ... veriexec: cannot update veriexec for /cf/var/validate/chroot/junos/usr/lib/libcurl.so.1: No such file or directory veriexec: cannot update veriexec for /cf/var/validate/chroot/junos/usr/lib/libcurl.so.1: No such file or directory veriexec: cannot update veriexec for /cf/var/validate/chroot/junos/usr/lib/libslax.so.3: No such file or directory veriexec: cannot update veriexec for /cf/var/validate/chroot/junos/usr/lib/libcurl.so.1: No such file or directory veriexec: cannot update veriexec for /cf/var/validate/chroot/junos/usr/lib/libext_bit.so.3: No such file or directory veriexec: cannot update veriexec for /cf/var/validate/chroot/junos/usr/lib/libext_curl.so.3: No such file or directory veriexec: cannot update veriexec for /cf/var/validate/chroot/junos/usr/lib/libext_xutil.so.3: No such file or directory Verified manifest signed by PackageProductionRSA_2018 Hardware Database regeneration succeeded Validating against /config/juniper.conf.gz cp: /cf/var/validate/chroot/var/etc/resolv.conf and /etc/resolv.conf are identical (not copied). cp: /cf/var/validate/chroot/var/etc/hosts and /etc/hosts are identical (not copied). Chassis control process: Chassis control process: chassisd Chassis control process: realtime-ukernel-thread is disable. Please use the command request system reboot. Chassis control process: Connectivity fault management process: rtslib: FATAL ERROR interface version mismatch: kernel=97 library=98,a reboot or software upgrade may be required Connectivity fault management process: mgd: error: configuration check-out failed Validation failed WARNING: Current configuration not compatible with /altroot/cf/packages/install-tmp/junos-12.3X48-D75.4-domestic