[CentOS] NTP server problem behind firewall

Artifex Maximus artifexor at gmail.com
Mon Sep 3 10:18:45 EDT 2012


On Mon, Sep 3, 2012 at 11:15 AM, Leonard den Ottolander
<leonard at den.ottolander.nl> wrote:
> On Sun, 2012-09-02 at 07:46 +0000, Artifex Maximus wrote:
>> Any idea what is wrong?
>
> The iptables rules you specify only allow clients from your local
> network access to your "proxy" ntp server. However, you do not specify
> any rules for eth1 to allow that ntp server to synchronise with the
> remote servers it is using. So unless you are using a local time source
> that might be your problem.
>
> Btw, when specifying rules for the external ntp servers you might want
> to specify IPs as well to restrict access.

Thanks. You are right ntp proxy is absolutely what I want. Mine
description was not clean probably. So this is the setup:

GPSNTP(10.0.1.99/24) - eth1 myserver eth0 - clients(10.0.0.0/24)

Because GPSNTP is on a physically separated network I need this proxy
for my clients. My server is able to synchronize with GPSNTP so rules
are fine for that (because my output chain is ACCEPT per default). My
clients whom are cannot synchronize with my server even if I allow NTP
port which I do not understand.

Bye,
a


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