NTP

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

Slackware

Update clock

Run the command as superuser:

• 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

Check the offset in milliseconds

• ntpdate -q pt.pool.ntp.org
• 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