Did you
sudo service ntp stop
sudo ntpd -gq
sudo service ntp start
? (as already pointed out here.)
Output should look like this:
[ ok ] Stopping NTP server: ntpd.
ntpd: time slew +0.001411s
[ ok ] Starting NTP server: ntpd.
Note that it can be slow:
time ntpd -gq
ntpd: time slew -0.007043s
real 0m7.063s
user 0m0.040s
sys 0m0.020s
You can also double check you are not talking to nothing;
grep -P "^server" /etc/ntp.conf
server 0.debian.pool.ntp.org iburst
server 1.debian.pool.ntp.org iburst
server 2.debian.pool.ntp.org iburst
server 3.debian.pool.ntp.org iburst
ping -c 1 0.debian.pool.ntp.org
PING 0.debian.pool.ntp.org (192.99.10.37) 56(84) bytes of data.
64 bytes from sexi.fawong.com (192.99.10.37): icmp_req=1 ttl=55 time=32.8 ms
--- 0.debian.pool.ntp.org ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 32.890/32.890/32.890/0.000 ms