How to set MacBook clock from GPS

In theory this should be fairly straight forward since (allegedly) the Mac operating system is a Unix/Posix one and you could therefore use standard tools to achieve this.

Sadly in more recent years Apple have started castrating macOS and one of the more recent and undesirable changes has been the removal of the standard ntp software from macOS. :(

Most of Apple's changes like this do have some merit in that they are supposed to improve security - the ntp protocol for example has had some security exploits discovered over the last couple of years but it does smack of throwing the baby out with the bath water. Apple now use their own custom 'timed' program which has none of ntp's extra capabilities.

However I believe a solution might still be possible even if it might now be much, much more complex. :(

Firstly we need a suitable GPS receiver. Traditional these were connected via serial cables and of course Macs do not have serial ports. This could be solved if needed by getting a suitable USB to serial adapter and these at least with Mojave are still possible to use. Fortunately I believe this should not be necessary.

I found the following product. It is a USB connected GPS receiver and claims to have Mac drivers. As far as I can see the Mac drivers/software merely let it show up as a pseudo serial device. This would make the device then in theory available to use with suitable applications e.g. a GPS tracking app to monitor your travels. Of course these days one would normally do such things on an iPhone or iPad.

See - https://www.zti-communications.com/z052-gnss-dongle-with-pps/

Now getting back to your requirement. Normally one would have a GPS receiver and then setup the ntp software on your computer to use the GPS receive as the clock source. As I mentioned in Mojave Apple have removed the ntp software.

In theory you could download and install the ntp software yourself since it is open source. This article seems to discuss how to do this - http://www.bensoftware.com/forum/discussion/2726/adding-ntp-server-to-securityspy/p1

Alternatively you could install a 'Docker' image to run ntp or probably simpler a Linux virtual machine via VirtualBox. VirtualBox should be able to link the Linux VM to a Mac USB device i.e. the GPS receiver. (The following was from another article.)

So I found the best solution for my situation. I ended up installed Docker CE for Mac, then running a docker instance of NTP. This achieved the desired results of getting an NTP service running on a the segregated network segment without having to have it routable to the internet.

Docker CE for Mac

docker NTP container on github

The Mac itself could then act as an ntp client to (whichever) ntp server solution you use.

See this https://time-nuts.febo.narkive.com/lwiAajBS/gps-ntp-update-on-mac-os-x-10-7-4 for information on setting up ntp to use a GPS source. It talks about using ntp on a Mac under a much older version which did include ntp but remember unless you install your own Mojave does not have ntp anymore.

Wow, impressive reply. :-)

Limnos wrote:

Wow, impressive reply. :-)

What no points? :-J

Hey, I did already mark it as "helpful"! You just need to impress another 4 people with it and it will turn into a real goldie. ;-)