Linux:
User one of the following commands to sync your servers time with the government time servers:
rdate -s time.nist.gov
ntpdate time.nist.gov
If you wish to change the timezone:
#set timezone to Eastern
cd /etc;
mv localtime localtimeOLD;
ln -s /usr/share/zoneinfo/US/Eastern /etc/localtime;
hwclock --systohc;
This would change the timezone to Eastern. In the /usr/share/zoneinfo/US/ folder their should be a file for each Timezone so you can link /etc/localtime to whichever zone you prefer.