JUNOS prior to 5.0 was based on FreeBSD 2.2.6.
JUNOS between 5.0 and 7.2 (inclusive) is based on FreeBSD 4.2.
JUNOS 7.3 and higher is based on FreeBSD 4.10.
JUNOS 8.5 is based on FreeBSD 6.1

That's all I can find about JunOS's FreeBSD version (not sure if it's even correct).

I don't see anything in Juniper documents about the corresponding FreeBSD version. Can anyone provide the FreeBSD version for newer JunOS releases up to 13.2?

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2 Answers 2


% strings jkernel-ppc-13.2R1.7|grep "FreeBSD: release"
$FreeBSD: release/7.3.0/sys/kern/kern_pmc.c 193634 2009-06-07 10:00:35Z fabient $

13.3 will be running 10.0. (edit: alas, this turned out not to be true)

  • 1
    Juniper uses the modified version of free BSD. So dont go on the FreeBSD version. Feb 22, 2014 at 1:46

The 15.1 + versions of Junos use the version 9+ version of freeBSD or upgraded version of freeBSD...it provides a lot of new features although it will change the file structure when implemented complete backups are necessary because data loss is possible.

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