Getting ntpd to work correctly on RHEL
When many new servers are delivered from the factory, the system clock is way off. Most UNIX systems run “ntpd” to keep the time in sync with internet time servers, which are, in turn synchronized against an atomic clock. This results in a system time that is very very close to the “actual” time of day. The downside, however, is that even a properly configured “ntpd” will not synchronize the system clock if it is too far out of sync with the time server. To remedy this, we first have to run “ntpdate” to get the system clock close to the correct time, and then enable “ntpd” to keep it there.
The first thing we have to do is “ntpd” to free up the port for “ntpdate”:
[root@server /]# /sbin/service ntpd stop
Shutting down ntpd: [ OK ]
This frees up the port for ntpdate. Next we run:
[root@server /]# /usr/sbin/ntpdate time.apple.com
Now the time should be set correctly. We then change the default time servers to something like the following in /etc/ntp.conf:
# --- OUR TIMESERVERS -----
time-a.timefreq.bldrdoc.gov
time-b.timefreq.bldrdoc.gov
time-c.timefreq.bldrdoc.gov
We can use any time server we want, but I like these and find them to be reliable.
Finally, start backup up your “ntpd” service, and your all set to go.
[root@server /]# /sbin/service ntpd start
Starting ntpd: [ OK ]
Remember to use “chkconfig” to make sure “ntpd” is enabled to come up when the system starts.
Discuss This Article
Post Tags (user submitted): RHEL ntp (158) - t (58) - rhel ntpd (41) - rhel4 ntp (38) - ntp RHEL (34) - rhel ntp server (27) - NTP RHEL4 (26) - ntpd RHEL (24) - ntpd RHEL4 (21) - rhel ntpdate (20) - rhel4 ntpd (19) - RHEL 5, NTP (17) - configure ntp RHEL (15) - RHEL configure ntp (13) - rhel ntp.conf (13) - RHEL 4 ntp (12) - ntpdate rhel (9) - rhel3 + ntp (9) - ntpd rpm (9) - rhel4 ntpdate (9) - rhel ntp howto (8) - rhel4 configure ntp (8) - rhel setup ntp (8) - ntp rhel 4 (7) - rhel4 ntp howto (7) - f (7) - ntpd howto (7) - rhel ntp configuration (7) - rhel4 ntp server (7) - ntp on rhel4 (6) - NTP setup RHEL (6) - rhel4 ntp setup (6) - setting up ntp rhel (6) - rhel 4 ntpd (6) - ntp.conf RHEL (6) - ntp +configuration +rhel (5) - configure ntp rhel4 (5) - rhel ntp setup (5) - RHEL4 ntp.conf (5) - rhel4 ntp rpm (5) - all (5) - rhel sync time (5) - ntp howto (5) - rhel ntpd configuration (5) - redhat ntpd (5) - rhel set time (4) - RHEL ntp config (4) - configure ntp on rhel (4) - rhel ntp sync (4) - ntp server rhel4 (4) - rhel4 ntp configuration (4) - ntpdate RHEL4 (4) - ntp server rhel (4) - setup ntp rhel (4) - ntp rpm RHEL4 (3) - rhel4 setup ntp (3) - "RHEL4" + "time server" (3) - rhel 5 ntpd (3) - ntpd config rhel (3) - rhel 5 ntpdate (3) - rhel timeserver (3) - rpm ntpd (3) - configuring ntpd on RHEL4 (3) - xntpd rhel (3) - redhat ntp howto (3) - configure ntp redhat 4 (3) - ntp rhel 3 (3) - "redhat ntp" (3) - rhel5 configure ntp (3) - RHEL set ntp (3) - rhel ntpd setup (3) - rhel4 "set time" (3) - ntpdate port (3) - ntpd rhel rpm (3) - ntpd RHEL4 rpm (3) - rhel synchronize ntp (3) - redhat rhel ntp (3) - rhel chkconfig (3) - rhel5 ntp (3) - ntp rhel 5 (3) - rhel ntp settings (3) - rhel time (3) - rhel 3 ntp (3) - ntpdate (3) - ntp rhel5 (3) - timeserver rhel (2) - rhel configure ntpd (2) - ntp.conf rhel4 example (2) - rhel3 ntpd server (2) - rhel ntp port (2) - rhel ntp rpm (2) - NTP server in RHEL4 (2) - ntpd not setting time correctly (2) - setup ntp server +rhel (2) - ntpd server rhel (2) - RHEL xntp (2) - ntpd service (2) - rhel ntp date (2) - ntp rhel4 configure (2) - rhel5 ntpdate (2) - ntp howto rhel (2) - RHEL4 set ntp (2) - RHEL setup ntpd (2) - rhel4 ntp sync (2) - how to setup a time server rhel (2) - configure ntp RHEL 4 (2) - rpm ntp rhel (2) - ntp for rhel4 (2) - ntp server on rhel5 (2) - rhel4 configure time (2) - ntp rhel configuration (2) - "ntp.conf" +RHEL4 (2) - ntp setup rhel5 (2) - RHEL4 NTP linux (2) - ntp linux rhel (2) - ntp + RHEL3 (2) - how to configure ntp in rhel5 (2) - setup ntpd RHEL (2) - ntp server RHEL 4 (2) - rhel 5 configure ntp (2) - setup ntp rhel4 (2) - "rhel 5" ntp.conf server (2) - sync with ntp server rhel (2) - RHEL 5 ntp server (2) - ntp rhel servers (2) - ntpd port (2) - rhel ntpd configure (2) - rhel3 ntpd (2) - set up ntp rhel (2) - howto setup ntpd (2) - linux ntpd port (2) - rhel set up ntp (2) - setup ntp on rhel4 (2) - start ntpd rhel (2) - RHEL ntp server howto (2) - RHEL ntpdate sync (2) - rhel ntpd server (2) - ntpdate RHEL4 rpm (2) - rhel ntp active directory (2) - ntpd service enable (2) - RHEL5 ntp.conf (2) - ntp.conf rhel5 (2) - ntp configuration +rhel4 (2) - RHEL 5 iptables ntp (2) - rhel4 time (2) - rhel4 ntp programmatic (2) - ntpd rhel 4 (2) - ntp rpm RHEL (2) - rhel4 ntp start (2) - configuring ntp rhel harden (2) -
I am using this time source:
64.236.96.53
It works good !
————————
Thank you for your explanation. It easy to read & understand. I solved my problem