NTP

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You can use the following command to check if it's enabled:<br>
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== Installing NTP<br> ==
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<pre> pgrep ntpd
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</pre>
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You can use the following command to enable NTP:<br>  
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<pre>yum install ntpd
 
<pre>yum install ntpd
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chkconfig ntpd on
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</pre>
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service ntpd start
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== Configuring NTP ==
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</pre>  
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Make sure your nameserver (DNS) is configured&nbsp; correctly (see [http://docs.telcobridges.com/mediawiki/index.php/TBLinux:How_to_change_the_ip_address Modify the dhcp client configuration]).<br>
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You can change the servers to synchronize NTP&nbsp;in /etc/ntp.conf
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=== Setting the time zone<br> ===
  
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You can change your local timezone with the /etc/localtime link<br>  
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Make sure that the host time zone is set properly. To modify the time zone go [http://kezhong.wordpress.com/2010/03/08/change-timezone-on-centos-5-4/ here]<br>
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=== Setting the DNS&nbsp;server<br> ===
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Make sure your nameserver (DNS) is configured correctly (see [[TBLinux:How_to_change_the_ip_address|Modify the dhcp client configuration]]).<br>
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=== Modify NTP Server List<br> ===
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Modify your ntp server list
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<pre>vim /etc/ntp.conf</pre>
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Change the server list for those closer to your server. List can be found [http://www.pool.ntp.org/en/ here]<br>Example for Canadian servers: <br>
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<pre>server 0.ca.pool.ntp.org
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server 1.ca.pool.ntp.org
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server 2.ca.pool.ntp.org
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server 3.ca.pool.ntp.org
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</pre>
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=== Synchronize the host date with the NTP&nbsp;server<br> ===
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'''Warning''': This may result is a jump in time of several minutes.<br>
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Use ntpdate to synchronize your server time with a NTP server.<br>
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Example showing a host synchronization with a Canadian server.<br>
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<pre>ntpdate 0.ca.pool.ntp.org
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</pre>
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=== Start NTP<br> ===
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You can use the following command to enable NTP:<br>
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<pre>chkconfig ntpd on
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service ntpd start
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</pre>
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== Verify NTP server status<br> ==
  
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To synchronize NTP: <br>
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To synchronize NTP:  
 
<pre>ntpq -p</pre>  
 
<pre>ntpq -p</pre>  
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It will display a list of servers and the server which is currently synced should be prepended by a '*'. For example:  
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<br>Example of host synched with barricade.rack9: <br>
 
<pre>    remote          refid      st t when poll reach  delay  offset  jitter
 
<pre>    remote          refid      st t when poll reach  delay  offset  jitter
 
==============================================================================
 
==============================================================================
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+cheezum.mattnor 129.7.1.66      2 u  91 1024  377  45.715    1.504  47.753
 
+cheezum.mattnor 129.7.1.66      2 u  91 1024  377  45.715    1.504  47.753
 
</pre>  
 
</pre>  
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In this case the host's time is synced with barricade.rack9.
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The '*' represent the current reference server<br>The '+' represent a potential backup reference server<br>The '-' represent a rejected reference server<br>

Revision as of 16:56, 11 February 2011

Contents

Installing NTP

yum install ntpd

Configuring NTP

Setting the time zone

Make sure that the host time zone is set properly. To modify the time zone go here

Setting the DNS server

Make sure your nameserver (DNS) is configured correctly (see Modify the dhcp client configuration).

Modify NTP Server List

Modify your ntp server list 

vim /etc/ntp.conf

Change the server list for those closer to your server. List can be found here
Example for Canadian servers: 

server 0.ca.pool.ntp.org
server 1.ca.pool.ntp.org
server 2.ca.pool.ntp.org
server 3.ca.pool.ntp.org

Synchronize the host date with the NTP server

Warning: This may result is a jump in time of several minutes.

Use ntpdate to synchronize your server time with a NTP server.

Example showing a host synchronization with a Canadian server.

ntpdate 0.ca.pool.ntp.org

Start NTP

You can use the following command to enable NTP:

chkconfig ntpd on
service ntpd start

Verify NTP server status

To synchronize NTP: 

ntpq -p


Example of host synched with barricade.rack9: 

     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*barricade.rack9 209.51.161.238   2 u 1001 1024  377   31.147   -0.369  20.074
+ip-72-167-42-82 204.123.2.5      2 u  754 1024  377  166.388  -29.692  28.223
+cheezum.mattnor 129.7.1.66       2 u   91 1024  377   45.715    1.504  47.753

The '*' represent the current reference server
The '+' represent a potential backup reference server
The '-' represent a rejected reference server

Retrieved from "https://docs.telcobridges.com/mediawiki/index.php?title=NTP&oldid=8631"
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