[ntp:questions] Three NTP servers, one strange IP-address in 'refid'

Steve Kostecke kostecke at ntp.org
Wed Apr 2 13:25:47 UTC 2014

On 2014-04-02, Sander Smeenk <ssmeenk at freshdot.net> wrote:
> Quoting Miroslav Lichvar (mlichvar at redhat.com):
>> > > I guess it could also be a IPv6 ref mangling issue?
>> > That could well be. We use IPv6 where we can.
>> For IPv6 addresses the refid is defined as first 4 bytes of the MD5
>> sum of the address. With 2001:7b8:3:32:213:136:0:252 (tt52.ripe.net)
>> that is 0xac023551, or in the quad-dotted notation.
> Miroslav, you're right. This is it. Thanks.
> I've changed everything over to IPv4 by not using hostnames anywhere.
> The IP is gone.

The refid is a 32-bit value used for loop detection. Only under IPv4
does the refid _happen_ to be an actual IP address. 

See slrnljo35n.4v1.kostecke at stasis.kostecke.net for more detail.

> I consider this a bug. 

Then feel free to add your voice to http://bugs.ntp.org/278

Steve Kostecke <kostecke at ntp.org>
NTP Public Services Project - http://support.ntp.org/

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