nanog mailing list archives
Re: ntp config tech note
From: Michael Sinatra <michael () rancid berkeley edu>
Date: Thu, 20 May 2004 21:08:43 -0700
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
Current thread:
- Re: ntp config tech note, (continued)
- Re: ntp config tech note Randy Bush (May 20)
- Re: ntp config tech note sthaug (May 21)
- Re: ntp config tech note C. Jon Larsen (May 21)
- Re: ntp config tech note Eric A. Hall (May 21)
- Re: ntp config tech note Mike Leber (May 24)
- Re: ntp config tech note Crist Clark (May 21)
- Re: ntp config tech note james edwards (May 21)
- Re: ntp config tech note Charles Sprickman (May 20)
- Re: ntp config tech note Pekka Savola (May 21)
- Re: ntp config tech note John Kristoff (May 20)
- Re: ntp config tech note Michael Sinatra (May 20)
- Re: ntp config tech note John Kristoff (May 21)
- Re: ntp config tech note Michael Sinatra (May 21)
- Re: ntp config tech note Stephen J. Wilcox (May 23)
- Re: ntp config tech note Tony Li (May 23)
- Re: ntpd config tech note redux Steven M. Bellovin (May 20)
- Re: ntpd config tech note redux Petri Helenius (May 20)
- Re: ntpd config tech note redux Suresh Ramasubramanian (May 20)