Set Your Clocks With Pooled NTP Servers
flok writes "Since we all want to have the time correctly set on our servers we all want to synchronize to some ntp-server. Not everyone has such an NTP server available, so that is why www.pool.ntp.org was started. If your server is synced to some discrete timesource like GPS or something like that you can also join the group to help this initiative!"
Unless you are running a stratum 2 server for hundreds of clients, it's polite to stay off the stratum 1 servers. Two or three us.pool.ntp.org servers do almost as well. My ISP's routers are stratum 3 NTP servers, and I use one of those.
I remember hearing a few years ago that the folks who ran tick and tock asked that only second-tier time servers sync to them, and that all the "leaf nodes" sync to a second-tier server. That's why I don't use tick or tock any more.
I write in my journal