NTP Server Best Practice?

[Kn10]

I have my Dahua cameras VLAN'd so they cant access the internet. But of course, without being able to access the internet NTP servers, the time tends to drift.

I could open the ports so they can reach the internet NTP servers.
Or perhaps set up an NTP server on the host BlueIris machine (which the cams can reach).

What are the security-conscious people doing to keep the camera times correct?

 

[saltwater]

Have your cameras point to your BI computer, as the Time Server (whatever the IP address is of your BI computer, and port number 123.

At your BI computer, download and install NetTime program, have that running as a service. Have the NetTime program check every 10 or 15 mins, or whatever to update your computer time. Job done. Screen image is my setting, the IP 192.168.30.99 is my BI computer. How secure is this, well I'll let others chime in.

 

[Kn10]

That did it. Thank you.
I had to open up the port on my BI machine as per these instructions.

I also had to press "Update Now" in Network time. My cams had the wrong time and I couldn't tell if the firewall rule was or wasn't working.
Turns out Network Time had the time wrong since the first installation, and it wouldn't check again for 11 hours.
The firewall rule WAS working between my BI host machine and the cams, but NetTime had the wrong time and gave that to the cams.
After pressing Update now, NetTime grabbed the real time from the internet servers, then the cams grabbed the correct time off NetTime.