[ntp:questions] forcing ntpd to query from a restricted interface or subnet

Harlan Stenn stenn at ntp.org
Sun May 6 20:09:55 UTC 2012

> > (AKA "nic") in ntp.conf was introduced late in the 4.2.5 cycle.
> > Something like the following should work for you:
> >
> > interface ignore all
> > interface listen eth0
> >
> > That should result in ntpd using only v4/v6 localhost and eth0's v4/v6
> > addresses.
> Thanks for that. I found a 4.2.6 built for Fedora 14 which did the
> trick. All I needed was -L in the end (it's not like I have 1k
> physical interfaces!). Definitely a shame that no one wants to
> maintain packages for RHEL6/CentOS6 for this. (I know, I know, if only
> I had more time...)

-L is mostly only useful under Linux, and the "interface" stuff works
all over.

You might not "appreciate" the numbering system NTP uses.  Going from
4.2.4 to 4.2.6 is a significant upgrade - the current NTP numbering
scheme uses ProtocolVersion.MajorVersion.MinorVersion[-pPointLevel].

Many other packages use Major.Minor.Point, and if that is what you are
expecting you would easily think there isn't a significant change
between 4.2.4 and 4.2.6.

To get a better idea of the changes involved, please look at the
ChangeLog file for 4.2.6 and see what has been done between 2006 and


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