Hi,

I would like all of my Linux servers to poll the NTP server every 10 minutes. Can someone tell me how to do that?

Thank you!

ntp polling is based on power of 2. The default min poll is 6 which is 64 seconds i.e 2^6 and the max poll is 10 which is 1024 seconds i.e. 2^10. The value to 10 minutes (600 seconds) is 512 seconds i.e a poll value of 9.

ntp uses a complex algorithm to find the best polling interval and if your system clock is stable should eventually settle at the default of 1024 seconds. You can set minpoll 9 and maxpoll 9 for a particular server in the /etc/ntp.conf file. If your time server or network is not stable you might need a faster polling interval then 10 minutes to keep the system clock accurate.

Thank you for your reply. I set my minpool to 9 and my maxpool to 9 and now it is polling every 64 seconds.

Please reread my post, as I understand how ntp works the polling interval is based on the power of 2

3 - 8 seconds
4 - 16 seconds
5 - 32 seconds
6 - 64 seconds
7 - 128 seconds
8 - 256 seconds
9 - 512 seconds
10 - 1024 seconds
and so on. There is no value for 600 seconds, Your closest choice is 9 i.e. 512 seconds.

Why do you think you need to change values? What problem are you trying to solve.

Hi,

Thank you for your response! I think my ntp.conf files are wrong....they had minpool and maxpool, instead of
minpoll and maxpoll.

By the way, what problem are you trying to solve if any and why do you want to change the polling interval?

Better to run ntpdate with the -u option via cron. In cron you can specify every 10 minutes. One less process (ntpd) to worry about. I think the port is udp 123.

The only time your really want to run ntpd is serving time to other.

The ntp daemon is both a client and a server. ntpdate via cron can keep the clock synchronized but it forces time jumps while ntpd keeps track of clock drift and slowly skews time which overall keeps better accuracy. The one downside is that ntpd expects the computer to connected to the internet.