Ntpdate not updating clock
The default is 1 second, a value suitable for polling across a LAN. This is most useful when behind a firewall that blocks incoming traffic to privileged ports, and you want to synchronise with hosts beyond the firewall. The slew adjustment is actually 50% larger than the measured offset, since this (it is argued) will tend to keep a badly drifting clock more accurate.
I am running Ubuntu on an ARM based embedded system that lacks a battery backed RTC. Thus, I use the NTP service to update the time to the current time.
This is most likely only a recent problem since I had power failures before and never noticed problems with time. When I stop the service and run ntpd manually May 5 autohome ntpd: ntpd [email protected] Fri May 18 UTC 2012 (1) May 5 autohome ntpd: proto: precision = 1.000 usec May 5 autohome ntpd: Listen and drop on 0 v4wildcard 0.0.0.0 UDP 123 May 5 autohome ntpd: Listen normally on 1 lo 127.0.0.1 UDP 123 May 5 autohome ntpd: Listen normally on 2 eth0 192.168.1.120 UDP 123 May 5 autohome ntpd: peers refreshed May 5 autohome ntpd: Listening on routing socket on fd #19 for interface updates # /etc/ntp.conf, configuration for ntpd; see ntp.conf(5) for help driftfile /var/lib/ntp/ntp.drift # Enable this if you want statistics to be logged.
#statsdir /var/log/ntpstats/ statistics loopstats peerstats clockstats filegen loopstats file loopstats type day enable filegen peerstats file peerstats type day enable filegen clockstats file clockstats type day enable # You do need to talk to an NTP server or two (or three).
I just stopped and restarted ntpd on my arch linux server, and I didn't see those lines.Behind this simple description, there is a lot of complexity - there are tiers of NTP servers, with the tier one NTP servers connected to atomic clocks, and tier two and three servers spreading the load of actually handling requests across the Internet.Also the client software is a lot more complex than you might think - it has to factor out communication delays, and adjust the time in a way that does not upset all the other processes that run on the server. That shall ensure that no two time syncing services are fighting and also to retain any kind of old behaviour/config that you had through an upgrade.NTP is a TCP/IP protocol for synchronising time over a network.Basically a client requests the current time from a server, and uses it to set its own clock.