[CentOS] ntp queries not being answered

[Nicolas Sahlqvist]

On Nov 20, 2007 2:05 PM, Engineer, Gaurav <gaurav.engineer at lmco.com> wrote:
>
>
>
> Hello All,
>
>
>
> My name is Gaurav, and I am tasked with configuring a linux box with NTP.
>
> I am having a problem that I hope you can help me with.
>
> We have installed CentOS V5 on 1 processor down in the lab.  The rest of the
> processors on the network are AIX boxes versions 3.2.5 and 5.2.  I worked
> through the entire initial NTP configuration; setup the /etc/ntp.conf file
> to point to the server, etc.
>
> Now when I run the ntpdate -d <address of server> on the linux box I get all
> the right information.
>
> Also, when I run the same command with the address for another non-linux box
> (AIX): ntpdate -d <address of non-linux box> I get all the right information
> again.
>
> The problem is that the linux box does not answer queries of the command to
> it.
>
> So if I enter the following on the non-linux box:
>
> Ntpdate -d <address of linux box>… all the values for offset, etc. are all
> zeroed out.  So the linux box is not passing any information back to the
> querying processor, even though the command works the other way (executed on
> the linux box querying the non-linux box).   Also, I don't see the usual
> "transmit….recieve" pattern for the command…. just the "transmit…transmit…".
>
> Are there any reasons that the box can query the server and other boxes
> successfully, but not answer queries sent to it?
>
> And in an effort to troubleshoot, I have commented out everything in the
> /etc/ntp.conf file except the server address to see if there was something
> in that file causing the problems, but that didn't work either.
>
>
>
> Do you have any information on this that could help me?  Anything at all
> would be appreciated.

Hi Gaurav,

Have you ensured that the firewall (iptables) are deactivated or got
the ntp port open for ntp queries from the AIX boxes?


- Nicolas