How can I check other NTP server's NTP version without query the server? NTPv3 and NTPv4 network packet is different, and I know I can just catch the packet and analysis it when ntpd is doing sync. However, I think it is not elegant enough. Do you have any other ways to determine whether a server is NTP v3 or NTP v4?
It's important to do this as NTP v3 are much less accurate(with tens of ms to hundreds of ms error on a typical internet) than NTP v4 (with several ms to tens of ms error on a typical internet).
NTPv4 is out at 2001(http://doc.ntp.org/4.1.0/release.htm), but it seems there is still some servers using ntpv3. I want to remove those servers from my peer list. How can it be finished?
I using a version 4 command at my server list, is that enough?
Check your time server website to find out for sure. Like me iam using a lot time.nrc.ca, and they direct the user to time4.nrc.ca on their website to use v4. I give the exemple as its best to check the website for information.
I been googling the same and checked various man pages seems to be when doubt assume Version 4. You can specify your client to user 1-4 and all will be compatible with version 4 ntpd Server.