ntp config tech note

Fri May 21 04:08:43 UTC 2004

Jared Mauch wrote:
> 
> 	I've found it useful on older machines (PCs with cheap clocks and
> oscilators) to cron ntpdate once an hour to prevent the clock from
> getting too far off by itself.  I've found the daemon doesn't do good enough
> of a job to sync on it's own...
> 
> 	I'm also wondering, how many people are using the ntp.mcast.net
> messages to sync their clocks?  what about providing ntp
> to your customers via the "ntp broadcast" command on
> serial links, etc..?

I run two stratum-1 servers and a few stratum-2s and I provide time via 
multicast (224.0.0.1), but I don't use it for my servers, except for 
testing and verification.  I am also providing anycast ntp, and, if the 
belt and suspenders weren't enough, I am experimenting with manycast. 
That's an NTPv4 feature where the *client* sends a multicast message to 
an administratively-scoped group soliciting servers and then the servers 
respond and set up associations.  From a client-configuration 
standpoint, it's about as convenient as multicast or anycast, but it's 
more accurate than multicast (since the servers set up true associations 
  with the client) and it allows you to do NTP authentication (which I 
think breaks with anycast).  It seems to work pretty well--the client 
builds up several associations as if they were all configured manually.

michael