Difference between revisions of "Ntp"

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NTP is the network time protocol. It allows you to fetch the current date/time from an internet time server. You can also use it to provide a network time service.
 
NTP is the network time protocol. It allows you to fetch the current date/time from an internet time server. You can also use it to provide a network time service.
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= Synchronize time =
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To sync the time with the time server ''pool.ntp.org'' [[find out your distribution]] and use the [[command]]
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== for SUSE ==
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sntp -P no -r ''ntp.company.com''
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== for other distributions ==
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sntp -s no ''ntp.company.com''
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= Keep time synchronized =
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To keep the time synchronized over reboots,
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* sync it one time:
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sntp -s no pool.ntp.org
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* have a file /etc/ntp.conf with one line:
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server pool.ntp.org
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* start the NTP service:
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/etc/init.d/ntp start
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* configure the NTP service to start on boot, e.g. for SUSE Linux:
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chkconfig ntp on
  
 
= Show time offset from time server =
 
= Show time offset from time server =
  # sntp timeserver.mycompany.com
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  # sntp ''timeserver.mycompany.com''
  2011 Aug 16 13:59:55.000224 + 0.000137 +/- 0.002426 secs
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  2014-02-18 10:09:11.391178 (-0100) '''+6.45592''' +/- 0.000427 secs
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Means that ''timeserver.mycompany.com'' is 6.5 seconds in the future compared to the local clock.
  
 
= Query status =
 
= Query status =

Latest revision as of 08:56, 8 June 2015

NTP is the network time protocol. It allows you to fetch the current date/time from an internet time server. You can also use it to provide a network time service.

Synchronize time

To sync the time with the time server pool.ntp.org find out your distribution and use the command

for SUSE

sntp -P no -r ntp.company.com

for other distributions

sntp -s no ntp.company.com

Keep time synchronized

To keep the time synchronized over reboots,

  • sync it one time:
sntp -s no pool.ntp.org 
  • have a file /etc/ntp.conf with one line:
server pool.ntp.org
  • start the NTP service:
/etc/init.d/ntp start
  • configure the NTP service to start on boot, e.g. for SUSE Linux:
chkconfig ntp on

Show time offset from time server

# sntp timeserver.mycompany.com
2014-02-18 10:09:11.391178 (-0100) +6.45592 +/- 0.000427 secs

Means that timeserver.mycompany.com is 6.5 seconds in the future compared to the local clock.

Query status

# /etc/init.d/ntp status
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*timehost1.local .PPS.            1 u  356 1024  377    1.404    0.049   0.154

Checking for network time protocol daemon (NTPD):                    running

Configure it

Edit /etc/ntp.conf, add your time server like this:

server myserver.domain