NTP Daemon Installation
Ubuntu comes with ntpdate as standard, and will run it once at boot time to set up your time according to Ubuntu's NTP server. However, a server's clock is likely to drift considerably between reboots, so it makes sense to correct the time occasionally. The easiest way to do this is to get cron to run ntpdate every day. BUT !!!
ntpdate is a bit of a blunt instrument - it can only adjust the time once a day, in one big correction. The ntp daemon ntpd is far more subtle. It calculates the drift of your system clock and continuously adjusts it, so there are no large corrections that could lead to inconsistent logs for instance. The cost is a little processing power and memory, but for a modern server this is negligible.
So lets install the NTP daemon to keep us in time.
sudo apt-get install ntp
Make NTP availible on the subnet your server is on.
# If you want to provide time to your local subnet, change the next line. # (Again, the address is an example only.) broadcast 192.168.3.255
sudo service ntp restart