Thanks, Darth. That’s one of the articles I’ve read. There must be some trick I’m missing. My clients will sync right up with the server...which normally would be a good thing. However, when I intentionally use bad keys, it also syncs right up. It doesn’t appear that the clients are actually trying to authenticate the NTP messages.
Red Hat has an article for configuring NTP with symmetric key auth at https://access.redhat.com/solutions/393663
Also, the ntp_auth(5) page any be useful for you - https://www.mankier.com/5/ntp_auth
Okay, you since you said you’re not a Linux guy in another post, I have to ask:
Are your clients running ntpd or using ntpdate? If ntpd, are what are you doing to cause it to re-read ntp.conf when you make changes to ntp.conf?
Oh, and how are you editing ntp.conf? On the linux machine, or on a windows machine and transferring to Linux?