[ntp:questions] Best practices for leaf nodes

Richard B. Gilbert rgilbert88 at comcast.net
Wed Nov 28 17:08:48 UTC 2007

Dag-Erling Smørgrav wrote:
> Can anyone point me to a document that describes best practices for a
> leaf node using SNTP to synchronize its local clock?  I am particularly
> interested in recommendations regarding how often to poll the server and
> how to behave if no answer is received.

Do NOT poll the server more often than once in 64 seconds! If you get no 
reply from a server, double the interval after each failure until you 
get to 1024 seconds.  If you get no reply after twenty-four hours, quit 
wasting your time and network bandwidth and try a different server.

This is documented in the RFCs for NTP and SNTP (RFC-1305 and RFC-4330.


I think you'll find RFC-1305 nearby but I'm too lazy to look it up for you.

Given the limitations of SNTP it is probably sufficient to poll two or 
three times a day.

Thank you for inquiring.  Several people have created mini-disasters by 
getting this wrong.  See; e.g. 

More information about the questions mailing list