[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


More information about the questions mailing list