I add the follow ntp servers and when I look at ntp.conf it changes - to _.
Configuration.
set system ntp server time-a.nist.gov prefer set system ntp server time-a.timefreq.bldrdoc.gov set system ntp server time-b.nist.gov prefer set system ntp server time-b.timefreq.bldrdoc.gov set system ntp server time-c.nist.gov prefer set system ntp server time-c.timefreq.bldrdoc.gov
ntp.conf
server time_a.nist.gov iburst prefer server time_a.timefreq.bldrdoc.gov iburst server time_b.nist.gov iburst prefer server time_b.timefreq.bldrdoc.gov iburst server time_c.nist.gov iburst prefer server time_c.timefreq.bldrdoc.gov iburst
Thanks in advance.