Hi Since “rogue” servers are rare, bumping up the number of servers fairly quickly gets you to a very high degree of confidence. Is that 5, 7, 9, or 11? It sounds like a wonderful topic for somebody’s thesis or dissertation :) Given that this is a free resource and that the network usage is negligible even with a dozen servers, the only real downside is being tagged as a resource hog.
Bob > On Nov 4, 2019, at 7:05 AM, Hal Murray <[email protected]> wrote: > > > [email protected] said: >> This is a pretty baseless fear. The servers in the ntp pool are constantly >> monitored and those that are off by more than 100ms are quickly removed >> (within 2-3 hours, IIRC). Of course, if you are already using one of those, >> then the removal will not help you. But you are most likely using 3-5 servers >> anyways, which means ntp will remove the "rouge" server on its own. > > It's more complicated than that. > > It depends on what code you are using and how you configured things. > > If you are using ntpd and you said in your ntp.conf > server <pool> > Then it grabs one and sticks with it until you restart ntpd. > > In the old days, it was common to use > server 0.pool > server 1.pool > server 2.pool > server 3.pool > That used the pool before the pool code in ntpd was working. I'm pretty sure > some distros set things up that way and some systems are probably still using > an old config file. > > The pool code is supposed to drop bad servers and get replacements. I'm not > sure of the details on what "bad" covers. It could be not responding at all > or it could be time not good-enough. I'll dig into the code if it matters. > > > If you aren't running ntpd (classic or ntpsec) then I don't know what happens. > > > -- > These are my opinions. I hate spam. > > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
