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NTP Redhat server

Posted on 2007-03-27
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Last Modified: 2013-12-06
Dear All
I have two Redhat servers in one LAN.
I want to synchronize the time between both, and i am in hurry,i want to do it now so can any instruct me until i can do it.

I already installed ntpd on the server.
NTP server:
Red Hat Enterprise Linux WS release 3 (Taroon)
IP: 10.0.0.202

NTP Client:
Red Hat Enterprise Linux AS release 4 (Nahant Update 2)
IP: 10.0.0.200

So
What i must write in /etc/ntp.conf at the server.
What is the command that i must add it to the crontab at the client.
What is NTP server i must use for synchronization.
Can any one send me an active config files.
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Question by:mukhtar2t
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by:Cyclops3590
ID: 18803500
my config

ntp.conf
---------------------------
server 129.6.15.29
-----------------------------

client cron entry
ntpdate -u 10.0.0.202

but I also have this for on my server cron
ntpdate -u 208.184.49.9
can't remember why I have that there.  most likely remnants from before it was a ntp server

also keep in mind after the ntp server is turned on, its stratum value will be very unreliable.  leave it go for a while and it will be reliable and then the in house client will actually use it for sync'ing the time
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Expert Comment

by:Tintin
ID: 18803951
Does your NTP server have access to the Internet?  If so, then it can sync off one of the many public NTP servers.

So on your NTP server, ntp.conf would have:

driftfile /var/lib/ntp/ntp.drift

server 0.pool.ntp.org
server 1.pool.ntp.org
server 2.pool.ntp.org
server pool.ntp.org

and on your NTP client/s, ntp.conf would have

server 10.0.0.202

No need for anything in crontab.  Just make sure NTP is enabled and running, by doing

chkconfig ntpd on
service ntpd start
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by:mukhtar2t
ID: 18806819
How i can know if it is working properly or not
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Expert Comment

by:suggestionstick
ID: 18807042
Hi

ntpq -p on the client ntp server will show your primary in the listing, and a reach value greater that 0 indicates sucess. a reach of 377 indicates that the last 8 sync attempts where sucessful

also if ntpdate 10.0.0.202 works on the box it will probably work when running ntpd server.

trev
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by:mukhtar2t
ID: 18807433
Ok
Now i installed the 10.0.0.202 as ntp server
and 10.0.0.200 as ntp client
i want to be sure that every thing is ok so:
- when i adjust the time at the server are the clients adjusted.
- when i adjust the time at a client is it adjusted back to the server.
- if change the timezone is it affect the synchronization.
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Accepted Solution

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suggestionstick earned 500 total points
ID: 18807786
Hi

1:When you adjust the time at the NtpD server, the client time will slowly sync to the new server time.

2:yes the client will slowly sync back to the server time.

3: if a change in time zone effects the ntp servers time, it will also effect the ntpd clients time.

Pls note: if you change the time by a large amount NTPD might fail to work, this is by Design. So if you change the time by a large amount on the server resync client by using ntpdate and then start syncing vi ntp


trev
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Expert Comment

by:Tintin
ID: 18812186
Time zone changes have *NO* effect whatsoever on NTP.  Timezones display the date/time as an offset from UTC.

Additionally, just about all ntpd startup scripts, will use ntpdate to ensure large time differences are sorted out.
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by:mukhtar2t
ID: 18814810
Thanks Tintin
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