2002-11-15
NTPD has a few advantages over other time synchronization clients. NTPD not only retrieves the time from a time server, but also runs as a daemon in the background. As it periodically gets the updated time from an NTP server NTPD will record how much drift has occured in /etc/ntp/drift. Over time it will know exactly how much its clock drifts and NTPD will update the time periodically to keep nearly perfect time even without the NTP server.
Installation on NTPD is quite simple. If its not already installed do this:
# cd /usr/ports/net/ntp # make install
Configuration of NTPD is a little more difficult. It depends entirely on what you want to do. I put a few sample /etc/ntp.conf files below. For more information about configuration options run “man ntp.conf”
You may have to create /etc/ntp.conf, and /etc/ntp if they don’t already exist.
Client that just updates time for itself
# vi /etc/ntp.conf server anytimeserver.com authenticate no driftfile /etc/ntp/drift
Client/Server for broadcasting time accross a network
# vi /etc/ntp.conf server anytimeserver.com broadcast 10.0.217.255 # for a local 8 bit subnet broadcast 10.0.218.255 broadcast 10.0.219.255 broadcast 10.0.220.255 broadcastdelay 0.008 authenticate no driftfile /etc/ntp/drift
Broadcasting Client
# vi /etc/ntp.conf broadcastclient yes authenticate no driftfile /etc/ntp/drift
One thing I learned is not to expect instant results. NTPD takes several minutes of warming up before it starts allowing time updates. I would wait 20 minutes after starting the daemon before concluding that its not working. Also right after running check the /var/log/messages for any errors.
For a list of public NTP servers visit:
http://www.eecis.udel.edu/~mills/ntp/clock1.html
