It’s very important to keep your system clock aligned to the exact timezone you reside. Following commands help to keep it in sync.
First select appropriate timezone
# dpkg-reconfigure tzdata
Above command actually copies your zoneinfo file from /usr/share/zoneinfo/ to /etc/localtime
So you can manually copy the file from zoneinfo directory to /etc/localtime on non-debian systems.
Now install following package to sync your system clock with Time Servers using Network Time Protocol (NTP)
# aptitude install ntpdate
# aptitude install openntpd
The ntpdate OpenNTPD keeps on checking time periodically to keep system time in sync with time servers.
OpenNTPD is a secure NTP daemon developed by OpenBSD Developers. (Theo de Raadt you r0ck ;))
You can also install ntp – a local ntp daemon as an alternative to OpenNTPD.
Thanks poisonbit for pointing out that ntpdate is now unmaintained and NTP or OpenNTPD is preferred over it. Check out first comment.
