If you have DNA, you can tell DNA to use the local server time, and point the server to a time source (time.gov etc.)
If you're have to reset the time every few weeks because of drift, you should run a calibration or three......
Go to a time source (I use the atomic clock in Colorado - 303-499-7111)
Send this command exactly at the beep:
CATII

ATE=, TIME=,CALIB=BEGIN;
Wait at least 55 hrs, go back to the same time source and send this command exactly at the beep:
CATII

ATE=, TIME=,CALIB=END;
Wait a week or two and repeat the process, but let the period between beginning the calibration and ending the calibration be a couple of weeks.
Repeat the process again in a month or 2, with a month or 2 between begin and end........
Once you've done this, you'll only need to calibrate once or twice a year.
I usually do a calibration right after daylight savings time changes.
Keep in mind that the clock display on your digital phones will NEVER be EXACTLY on the second with your standards based time source........there's always a few seconds difference.
A CADAP; print from a terminal will be correct with your time source once your system is in good calibration.
If you have a Frequency Dump set, you have to end and re-initiate it after every manual time change.
Good luck,
Dave Strang