Restore SRX Configuration with USB

Your network is down! Panic is setting in, users are complaining, you need to get the broken SRX device replaced with a spare ASAP! Hopefully you have a spare, or at least opted for same day support.

Then you realise that you've got to find the config file to get the replacement SRX back up and running. Then you can't find a console cable. You're having a really bad day!

We love tools that make it easier in these kind of situations. SRX has a great (but not very well known) feature that can help you out here. It's called USB Auto Install.

There is a great Juniper Learning Byte video on YouTube about USB Auto Install. It covers how easy it is to install new Junos software on an SRX, but what is leaves out is that you can also use this process to get configuration on there too. 

Here are the steps:

  • Find a FAT32 USB flash drive
  • Format it / clear all other files off (especially people using Mac OS X, you'll need to get on the Terminal for this as the finder stores all kinds of things in there).
  • You'll need to put a couple of files on there:
    • junos-config.conf - your full Junos configuration, in stanza format.  You can download this from OneConfig's device details window.
    • autoinstall.conf - just a blank file, e.g. "echo " " > F:\autoinstall.conf"
    • Junos software image, it needs to be the "junos-srxsme" name (e.g. junos-srxsme-12.3X48-D20.4-domestic.tgz)
  • Power up the SRX, insert the USB in the front
  • After some time the lights will all start flashing
  • Hold in the "config reset" button, use a pen
  • When all the lights go green, you're good to go. Pull out the USB and the SRX will reboot with the new software and the configuration in place.

There is also a Juniper KB article that goes in to more detail.

OneConfig can store your configuration backup - simply enable it by ticking the box in the Device Settings window. Or turn it on for all new devices via Settings -> Device -> Enable config backups.

If you have any questions about USB Auto Install for SRX with configuration added, please feel free to contact me.

By Martyn Lomax (