If you need to quickly jump the system time to the correct time.

Warning, before you do this, you should shut down any databases, etc... running on the server.

ntpdate time.nist.gov

set the time on the CMOS/BIOS/RTC clock from systemtime

hwclock -w

If you don't have an NTP service available, you can set the clock based on the current time on another server

date +%Y%m%d%T -s "`ssh user@remoteserver 'date "+%Y%m%d%T"'`"