[ntp:questions] handling falseticker
catia.lavalle at bechtle.com
catia.lavalle at bechtle.com
Tue Feb 17 07:51:43 UTC 2009
Hallo,
I have the following configuration Stratum 0 configuration:
1 x Stratum 0 (DCF "Clock") --> 1 x Stratum 1 (let's give it the IP
10.1.1.1)
1 x Stratum 0 (GPS "Clock") --> 1 x Stratum 1 (let's give it the IP
10.1.1.2)
I do not have (for security policy) the possibility to give any other
alternative (extern) time source to the Stratum 2 Servers.
This means that my Stratum 2 Servers have only 2 servers. Obviously this
configuration is not "falseticker save".
I have a monitoring active which warns me if the time offset between the 2
Stratum 1 server gets bigger than a fixed limit.
In such a situation anyway the NTP daemon on the Stratum 2 servers would
mark one of the 2 Stratum 1 servers as a falseticker and "ignore" the time
coming from it.
Since there are only 2 Stratum 1 server to choose from the "voting"
decision do not really apply, in such a way that the decision that the NTP
on the Stratum 2 servers take upon "ops! there is a falseticker. Which one
is falseticker?" is rather casual (I guess).
Say they mark the server 10.1.1.1 as falseticker.
remote refid
===================
*10.1.1.1 .GPS.
x10.1.1.2 .DCF.
127.127.1.1 .LOCL.
At this point I will get a warning from my monitoring, I will check
manually with an external source which time really is and have a look to
the decision that NTP on the Stratum 2 Server took. Say I realize that the
decision taken is wrong: the 10.1.1.1 is not the false ticker, the true
false ticker is 10.1.1.2
What should I do? I mean is there a way to force NTP "on the fly" to
change it's mind? I have in mind something like a command line saying
"force to trust server 10.1.1.1" (which simultaneously automatically will
imply "then ignore 10.1.1.2 since this means it is the true
falseticker")? ==> to force the following "switch"
remote refid
===================
x10.1.1.1 .GPS.
*10.1.1.2 .DCF.
127.127.1.1 .LOCL.
Sure I could reconfigure ntp.conf with a prefer on the 10.0.0.1 server,
and restart the daemon (would it work? I guess so), but I do not really
like it, I find it to "permanent".
thanks
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