time.nist.gov

ntp.fudan.edu.cn [復旦]

timekeeper.isi.edu

subitaneous.cpsc.ucalgary.ca

usno.pa-x.dec.com

time.twc.weather.com

swisstime.ethz.ch

ntp0.fau.de

ntp3.fau.de

time-a.nist.gov

time-b.nist.gov

time-nw.nist.gov

nist1-sj.glassey.com

210.72.145.44