time.windows.com ntp.mobatime.ru time.nist.gov clock.isc.org timekeeper.isi.edu usno.pa-x.dec.com tock.usno.navy.mil tick.usno.navy.mil chrimr.utoronto.ca ntp.pipex.net fartein.ifi.uio.no ntp1.sp.se ntp1.cs.wisc.edu ntp1.gbg.netnod.se ntp2.cs.wisc.edu tock.usno.navy.mil ntp3.cs.wisc.edu ntp.cs.strath.ac.uk time1.stupi.se tick.stdtime.gov.tw tock.stdtime.gov.tw time.stdtime.gov.tw На работоспособность не проверял.
time.nist.gov time.windows.com ntp.time.in.ua ntp2.time.in.ua ntp3.time.in.ua time1.free.net time2.free.net time3.free.net.