[time-nuts] Discipline an oscillator with NTP?

Steve Longcor swlongcor at comcast.net
Sun Jul 24 00:31:32 UTC 2011


ntpd is both a client (getting time info from other ntp servers) and a 
server (responding to requests from other clients on the network.)  
Access to the server part is controlled by firewall rules and "restrict" 
lines in the ntp.conf file (see example below).  An explanation of these 
can be found at http://support.ntp.org/bin/view/Support/AccessRestrictions

Steve

----------
# /etc/ntp.conf, configuration for ntpd; see ntp.conf(5) for help

driftfile /var/lib/ntp/ntp.drift

# Garmin 18xLVS GPS + PPS
# mode 1    use $GPRMC sentence
server 127.127.20.1 mode 1 minpoll 4 prefer
# flag1 1    enable PPS signal processing
# flag3 1    kernel discipline
fudge 127.127.20.1 flag1 1 flag3 1

# North-American Pool servers for backup/sanity check
server 0.north-america.pool.ntp.org
server 1.north-america.pool.ntp.org
server 2.north-america.pool.ntp.org

# Access control configuration; see 
/usr/share/doc/ntp-doc/html/accopt.html for
# details.  The web page 
<http://support.ntp.org/bin/view/Support/AccessRestrictions>
# might also be helpful.
#
# Note that "restrict" applies to both servers and clients, so a 
configuration
# that might be intended to block requests from certain clients could 
also end
# up blocking replies from your own upstream servers.

# By default, exchange time with everybody, but don't allow configuration.
restrict -4 default kod notrap nomodify nopeer noquery
restrict -6 default kod notrap nomodify nopeer noquery

# Local users may interrogate the ntp server more closely.
restrict 127.0.0.1
restrict ::1
----------

On 7/23/2011 4:53 PM, Scott Newell wrote:
> At 06:45 PM 7/23/2011, Don Latham wrote:
>> than a client. I looked up man ntpd, and it seems at first glance to be
>> a Linux/Unix client that will sync up a local computer. I want to
>> generate a network server that ntpd or other clients can access. Perhaps
>
> ntpd is the server.
>




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