[ntp:questions] Best practice: re-resolve server IP address before each poll/query
Nero Imhard
nim at pipe.nl
Tue Jun 12 20:59:51 UTC 2007
Richard B. Gilbert wrote:
> day! An NTP client will query as frequently as once per minute and
> doing a DNS lookup each time would border on the absurd.
I don't think the original poster meant that the application should do
direct queries on the wire. It is a resolver's job to cache, and only
repeat queries after the cached answers have expired. An application
should be free to ask any time it wants to.
> IP addresses do
> not change all that often and a system that did change IP addresses
> frequently would not be much use as an NTP server.
I believe it's a bad thing to build such (or any) assumptions into a
system. DNS has TTL-values precisely to handle such issues. I'd say, use
them.
N
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