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Install Junos OS Software Package

You can use this procedure to upgrade Junos OS on the device with a single Routing Engine.


Junos OS is delivered in signed packages that contain digital signatures to ensure the Juniper Networks software is running. When installing the software packages, Junos OS validates the signatures and the public key certificates used to digitally sign the software packages. If the signature or certificate is found to be invalid (for example, when the certificate validity period has expired or cannot be verified against the root CA stored in the Junos OS internal store), the installation process fails.

To install software upgrades on your device with a single Routing Engine:

  1. Download the software package as described in Downloading Software Packages from Juniper Networks.
  2. If you have not already done so, connect to the console port on the device from your management device, and log in to the Junos OS CLI. (For instructions, see Configure Junos OS on an EX4100 and EX4100-F Switch for EX4100 Series devices.)
  3. (Optional) Back up the current software configuration to a second storage option. See the Junos OS Installation and Upgrade Guide for instructions on performing this task.
  4. (Optional) Copy the software package to the device. We recommend that you use FTP to copy the file to the /var/tmp/ directory.

    This step is optional because Junos OS can also be upgraded when the software image is stored at a remote location. These instructions describe the software upgrade process for both scenarios.

  5. Install the new package on the device:

    Replace package with one of the following paths:

    • For a software package in a local directory on the device, use /var/tmp/package.tgz.

    • For a software package on a remote server, use one of the following paths, replacing package with the software package name.

      • ftp://hostname/pathname/package.tgz

      • http://hostname/pathname/package.tgz


    If you need to terminate the installation, do not reboot your device; instead, finish the installation and then issue the request system software delete package.tgz command. This is your last chance to stop the installation.

  6. Reboot the device to load the installation and start the new software:
  7. After the reboot has completed, log in and use the show version command to verify that the new version of the software is successfully installed.