[ntp:questions] Re: two ntp servers
rancidmoth at yahoo.com
Mon Feb 20 21:44:26 UTC 2006
no it seems to definitely be reaching them. i have checked using the
dmpeers command. also running the ntpq -p i get the exact same thing as
what is on the other box. also note that in my trials i have set a machines
time from off the other machine and made them perfectly in synch. when i
then take that machine and point it to the upstream server it then drifts
until it is three minutes ahead. i just dont get it. odd dont you think?
"John Pettitt" <jpp at cloudview.com> wrote in message
news:43F4FDCA.3070402 at cloudview.com...
> rancid moth wrote:
>> not being very familiar with the ntp protocol, and currently introducing
>> myself to it properly (i.e. have always used though never dug deeply into
>> it), i have established two ntp services on two different Linux machines.
>> Both ntp servers are pointing to the _same_ upstream server. There is a
>> four minute difference in time on the machines. Lets call them machine A
>> and B. initially i established them to the same time, by synching B's
>> from A which itself was synched from the upstream internet ntp server.
>> If i
>> then modify B's config to also synch from the same upstream source, B,
>> enough time, will drift 4 minutes ahead of A. Can someone please point
>> to an introductory explanation as to why/how this can occur.
> Basically your setup isn't working for some reason - if you do "ntpq -p"
> on both boxes you'll
> probably see that one or both of them are not actually talking to the
> upstream. As a general rule
> you need at least four upstream servers for stability (see
> www.pool.ntp.org for how to get more
> servers). It's probably a good idea to peer the two local servers and
> then point them at diverse
> (overlapping is ok) groups of upstream servers as this will give to a very
> robust setup.
> If I had to guess I'd say that a firewall somplace is blocking the ntp
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