NTP

NTP is a TCP/IP protocol for synchronizing time over a network.

Slackware

Update clock

Run the command as superuser:

   1 ntpdate pool.ntp.org
   2 sudo ntpdate pool.ntp.org

Date and time should be stored in UTC.

Info on slack docs:

• http://docs.slackware.com/howtos:network-services:ntp

Enable the service:

• chmod 755 /etc/rc.d/rc.ntpd

Start the service manually:

• /etc/rc.d/rc.ntpd start
• /etc/rc.d/rc.ntpd status

Add ntp server

• Edit /etc/ntp.conf

• add server pt.pool.ntp.org

   1 server  127.127.1.0     # local clock                                           
   2 fudge   127.127.1.0 stratum 10
   3 server pt.pool.ntp.org
   4 driftfile /etc/ntp/drift
   5 # Don't serve time or stats to anyone else by default (more secure)             
   6 restrict default noquery nomodify
   7 # Trust ourselves.  :-)                                                         
   8 restrict 127.0.0.1

Check the offset in seconds

• ntpdate -q pt.pool.ntp.org # offset in seconds
• ntpq -pn

CentOS

• yum install ntp
• service ntpd start
• chkconfig ntpd on
• service ntpd stop
• ntpdate pt.pool.ntp.org # sync clock
• service ntpd start
• ntpdate -q pt.pool.ntp.org
• ntpq -pn

Ubuntu / Debian

• apt-get install ntp
• ntpdate -q pt.pool.ntp.org
• service ntp stop
• ntpdate pt.pool.ntp.org
• service ntp start
• ntpq -pn

FreeBSD 9.0

Run the command:

• ntpdate pool.ntp.org

Check the UTC date:

• date -u

Edit the file /etc/rc.conf:

• ntpd_enabled="YES"

Start and check the NTPD service status:

• /etc/rc.d/ntpd start
• /etc/rc.d/ntpd status

Sync summer time Slackware

• timeconfig # set HW clock to UTC
• /etc/rc.d/rc.ntpd stop
• ntpdate pt.pool.ntp.org
• /etc/rc.d/rc.ntpd start

Windows

• net start w32time
• w32tm /config /manualpeerlist:pt.pool.ntp.org
• w32tm /resync /force