server time.cloudflare.com iburst nts server nts1.time.nl iburst nts server sth1.nts.netnod.se iburst nts server ptbtime1.ptb.de iburst nts minsources 2 authselectmode require driftfile /var/lib/chrony/drift ntsdumpdir /var/lib/chrony leapsectz right/UTC makestep 1.0 3 rtconutc rtcsync cmdport 0