What is the preferred etiquette when synchronizing to a public server?
If the listing at http://www.eecis.udel.edu/~ntp says to notify before before using a server, then you should send email and wait until you get an affirmative reply before using that server. Some public timeservers are listed as “open access” with no notice required (especially the secondaries). Very public-spirited. I have one of these (stratum-2 right now) at ntp-cup.external.hp.com. You should probably have no more than three of your timeservers using any individual public timeserver. Let all of your internal clients be served by those three (or three-groups-of-three). The most popular time servers are highly overloaded, recommending that you should avoid them if possible. The official etiquette is described in http://www.eecis.udel.edu/~mills/ntp/servers.htm, section Rules of Engagement.
