You can find several download methods on the ntpsec website.
As of 2017-07-29, the is no port for ntpsec yet. So on FreeBSD you have to compile it yourself. Fortunately, this is not difficult.
You will need Python to build ntpsec. Additionally, many of the helper programs are written in Python. In this article, I’ll be using Python 3.6.
The asciidoc program and the DocBook stylesheets are needed to build the documentation.
Building the software
To build the software, I downloaded the source distribution from the FTP site. Cloning the repo from gitlab also worked.
Downloading a tarball from gitlab or github would complain about a missing .autorevision-cache file during the build.
> python3 waf configure --prefix=/usr/local --python=/usr/local/bin/python3 > python3 waf build > cd build/main/ntpclients/ > sed -i '' -e 's/env python/env python3/' ntp* > cd - # python3 waf install
The sed command is necessary because the scripts call python, not python3.
The standard /etc/rc.d/ntpd seems to work well, provided I set the following in my /etc/rc.conf:
ntpd_enable="YES" ntpd_program="/usr/local/sbin/ntpd" ntpd_sync_on_start="YES"