ntpd is the Network Time Protocol daemon.
Install ntpd with:
# apt-get install ntp
ntpd will use Ubuntu's pool of time servers by default. This list can be modified by editing /etc/ntp.conf.
ntpd will attempt to bind to IPv6 addresses by default. On systems without IPv6 connectivity, this will cause errors in the system log every 5 minutes. To disable IPv6, edit /etc/default/ntp by changing the top line to read:
followed by a restart of ntpd.
The status of ntpd can be seen with the commands:
ntpq -c rl