[$] The NTP pool system

NTP, the Network Time Protocol, quietlyand without much fuss performs the critical internet function of knowingthe correct time. Using it, a computer with imperfect communications linksmay join a distributed community of servers, each of which is eitherdirectly attached to a reliable clock, or is trying to best synchronize itsclock to one or more better-synchronized members of the community. The NTPpool system has arisen as a method of providing such a community to theinternet; it works well, but is not without its challenges.