[ntp:questions] Re: A Question about Configuring and Starting NTP

Richard B. Gilbert rgilbert88 at comcast.net
Fri Sep 23 11:09:21 UTC 2005


OCDave wrote:

>Hello
>
>This is my first post on this group - please excuse me if
>the topic seems really simple
>
>I'm trying to implement NTP on two Linux Boxes - one is
>Red Hat 9 and the other is Fedora Core 3
>
>On both boxes, I enter three IP addresses in /etc/ntp.conf
>I got these addresses from a list of Stratum Two Time Servers
>on ntp.isc-org
>
>The addresses are :
>
>Ntp2.sf-bay.org  	204.74.68.55
>Ntppub.tamu.edu	128.194.254.9
>Ntp.ourconcord.net	216.204.156.2
>
>I entered these IP addresses into /etc/ntp.conf  and
>Start the service.
>
>When I run ntpq -p I get the following
>
>     remote           refid      st t when poll reach   delay   offset
>jitter
>==============================================================================
> zorac.sf-bay.or .INIT.          16 u    - 1024    0    0.000    0.000
>4000.00
> ntp3.tamu.edu   .INIT.          16 u    - 1024    0    0.000    0.000
>4000.00
> ourconcord.net  .INIT.          16 u    - 1024    0    0.000    0.000
>4000.00
>*LOCAL(0)        LOCAL(0)        10 l   51   64  377    0.000    0.000
> 0.002
>
>Which shows there is no connection to the time servers.
>
>I can do traceroutes to each time server, so I know they are online.
>
>Should I enter the names/IP addresses in the Step-Tickers or
>The Ntpservers ?
>
>Any comments would be appreciated
>
>Thanks
>
>Dave Harman
>
>  
>
I checked the first two servers you listed with ntpdate -u -d.  Both are 
working NTP servers with good time.   The -u tells ntpdate to use a 
non-privileged port, necessary because the ntp daemon was running and 
port 123 was not available.   The -d tells it to query the server and 
report the results without trying to set my clock.   You can try the 
same thing.   If it works; i.e. you get replies from the server, you are 
having a problem with port 123; it's either blocked by a firewall or in 
use by something else.  

Your firewall, if you have one, must allow UDP on port 123.

Other than that, you should be configuring a minimum of four servers.   
With only three, if one fails, ntpd has no way to determine which of the 
remaining two is more nearly correct!




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