Download the VMWare appliance here:
http://www.juniper.net/support/downloads/?p=firefly#sw
You will find the latest version v12.1X47-D20, file size is around 230 Mb.
Note: You will need an authorized login account to download the appliance. Google v12.1X47-D20 it is also available on some file sharing websites in case you don't have one.
Download and extract with 7zip or winrar. We only need one file.
Run Oracle VM Manager and add create a new Virtual Machine. Click "Next"
Set the memory size to 1 GB or 2 GB if you are planning to run and configure a lot of security features and you have lots of available physical memory on board.
Apply the following settings:
Under the Motherboard Tab, check the Extended Features.
Under the processor tab, allocate 2 CPU and enable PAE/NX
Disable Audio, Enable Serial Port
Enable Network Adapter (not connect) 4 is currently available (8 is supported)
Click "OK" to close the Settings. You can close the VM Virtual box and create a notepad and type the following commands. Copy and paste it on the command prompt and then run VM Virtual Box to see the changes.
Configure GNS3 Preferences under Virtual Box and load the cloned vSRX virtual machine.
Create a simple topology and turn on the devices.
Once the vSRX client is up, access it via console and login as root with no password and you're ready to play with Juniper OS.
