[ntp:questions] what is refid in ntpq -pn

Nathan Stratton Treadway nathanst+ntp-questions at ontko.com
Wed May 17 18:04:00 UTC 2017

On Sat, May 13, 2017 at 12:46:28 -0700, Hans Mayer wrote:
> On 7 May 2017, at 00:12, Steven Sommars <stevesommarsntp at gmail.com> wrote:
> > If using the IPv6 address family, it is the first four octets of the MD5 hash of the IPv6 address.
> OK, now I understand, this makes sense. I am using dual stack on my application server as well as on all ntp server. And I am using DNS names in ntp.conf. I see similar refid's because all my application server have identical 4 ntp upstream server.
> But hard to verify. Has somebody a tool to convert an IPv6 in usual notation to change into  32 hex-chars without ":" character ? 

If you are asking for something that converts IPv6 addresses into the
NTP Refid format so you can determine which upstream address is
indicated by a particular Refid, there's some sample Python code
available at:


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