[ntp:questions] Re: NTP does not sync when using pool.ntp.org

Adrian 'Dagurashibanipal' von Bidder grazdan at fortytwo.ch
Mon Oct 6 17:32:35 UTC 2003

Clinging to sanity, Dale Worley mumbled in his beard:

> My recollection is that if you have one address listed as a server
> twice, one of them will "reach" and the other won't.  OTOH, you *are*
> getting timing information from clock2.redhat.com, so it's OK.  The
> real problem is that pool.ntp.org is giving you the same address
> twice.

This is a problem we can't solve without ntpd knowing about DNS round robin
explicitly (to my knowledge, nobody is working on this right now, though).
This behaviour depends heavily on your local resolver library (and possible
cache daemon) and the caching nameservers in the chain from your site to
the authoritative servers for pool.ntp.org.

This is one of the reason why I recommend use of pool.n.o as default config
for those who want ntp to 'just work', but recommend manually selecting
timeservers for anybody interested enough to tweak their ntp.conf (the DNS
zones at pool.n.o can be a good starting point for this, though).

(Hmm. One thing you might want to try: have a wrapper script around ntp
startup to change resolv.conf before starting ntpd to use one of the
pool.ntp.org nameservers directly, and then changing it back after ntpd has
made its DNS lookups).

-- vbi

featured link: http://fortytwo.ch/smtp

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