NTP issue Continued

[Andrew Bacchi]

Andrew,

I haven't followed this thread for long so this may have already been 
suggested.

I have this line in my iptables file to allow ntp communication.  You 
may already have it, if not add it and restart iptables.  This works on 
both RHAS 3 and RHAS 4.   You might check in /var/log/messages for 
anything concerning ntp, that may give you some clue, also check 
/var/log/security

Good luck.

#Allow NTP.
-A INPUT -p udp -m udp -s 0/0 --sport 123                   -d 0/0 
--dport 123  -j ACCEPT

Andrew.Bridgeman at corusgroup.com wrote:
>
>
> I am still having problems getting 40 redhat machines to use ntp and
> synchronise with our Windows 2003 Cluster. I have tried a couple of things
> suggested by people but have had no luck in fixing the issue. It seems that
> when I put either the IP of the cluster, the name of the cluster or the
> fully qualified name of the cluster in the config files the ntp service
> communicates with the Windows cluster straight away and all the machines
> are synchronised OK. The problem comes when i leave them afterwards for an
> hour or a day or even a week and look back at the time on the machines and
> they are all different.
>
> I read on the net that the communication used with ntp is UDP over port 123
> and was wondering if i have  some kind of polling issue after the initial
> start-up of ntp. Does anyone know more detail on how the ntp part works.
> i.e How often does is poll the cluster server for the time or is there a
> way of checking the communication on that port is working.
>
> Any  help on this would be much appreciated.
>
> Regards
>
> Andrew Bridgeman
>
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