NTP

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You can use the following command to check if it's enabled:<br>  
 
You can use the following command to check if it's enabled:<br>  
<pre>ntpdate -q</pre><pre>chkconfig --list | grep ntpd</pre>
+
<pre>ntpdate -q</pre><pre>chkconfig --list | grep ntpd</pre>  
If all the columns are 'off', then it's not enabled.
+
If all the columns are 'off', then it's not enabled.  
  
 
You can use the following command to enable NTP:<br>  
 
You can use the following command to enable NTP:<br>  
Line 8: Line 8:
 
Then use the following command to start it:<br>  
 
Then use the following command to start it:<br>  
 
<pre>service ntpd start
 
<pre>service ntpd start
</pre>
+
</pre>  
 
+
You can check if the time is in sync using:<br>  
You can check if the time is in sync using:<br>
+
 
<pre>ntpq -p</pre>  
 
<pre>ntpq -p</pre>  
It will display a list of servers and the server which is currently synced should be prepended by a '*'. For example:
+
It will display a list of servers and the server which is currently synced should be prepended by a '*'. For example:  
<pre>
+
<pre>     remote          refid      st t when poll reach  delay  offset  jitter
    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
 
*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
 
+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
 
+cheezum.mattnor 129.7.1.66      2 u  91 1024  377  45.715    1.504  47.753
</pre>
+
</pre>  
 
In this case the host's time is synced with arricade.rack9.
 
In this case the host's time is synced with arricade.rack9.

Revision as of 17:38, 1 December 2010

You can use the following command to check if it's enabled:

ntpdate -q
chkconfig --list | grep ntpd

If all the columns are 'off', then it's not enabled.

You can use the following command to enable NTP:

yum install ntpd
chkconfig ntpd on

Then use the following command to start it:

service ntpd start

You can check if the time is in sync using:

ntpq -p

It will display a list of servers and the server which is currently synced should be prepended by a '*'. For example:

     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

In this case the host's time is synced with arricade.rack9.

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