Fwd: ntp help
On Thu, Nov 11, 2010 at 12:35, Robert Moskowitz <email@example.com> wrote:
On 11/11/2010 11:20 AM, firstname.lastname@example.org wrote:
> I am trying to sync via NTP locally (since I have no Internet access).
> None of the NTP stuff I read on the net seems to work right. *I mean it works fine setting up a client going to something like 0.pool.ntp.org but when I want to make my LInux box a server, and I do an ntpdate to it from another machine,
> it says no suitable server found. *I have tried every possible combination of restrict, broadcast, multicast. *Followed directions in the examples but
> nothing works. *Also "iptables-save" shows no iptables stuff set at all, so there is no firewall blocking it.
> Maybe I could ask my question and someone could tell me how to configure?
> There are 4 machines:
> 1. 10.5.1.50
> 2. 10.5.0.20 / 192.168.1.100
> 3. 10.6.1.50
> 4. 10.6.0.20 / 192.168.1.101
> The 10.5s cannot reach the 10.6s (except roundaboutly through the 192
> network). *The two 192 machines are connected directly to each other.
> You can get back and forth between them
> I want to set it up so that, and it doesn't matter which way), one of
> the 191.168.1.X machines NTP syncs to the other, and then
> the 10.5.1.50 syncs to 10.5.0.20 and the 10.6.1.20 syncs to 10.6.0.20.
> How do I set the ntp.conf files? *Remember there is no external internet
> on any of the machines, and the 10.5 machines cannot reach the 10.6 machines and v.v. (except the 10.X.0.20 machines can reach each other through the 192 network). *Also I am not allowed to use the 192 machines as routers for the 10.X.1.50 machines.
I have 3 systems here that are my internal NTP servers. *They are set up
to go out and get time, and my clients all look to them for time.
The files you need to work with are:
For /etc/ntp.conf you need to control how your local clients interact
with the server, like:
restrict 192.168.128.0 mask 255.255.255.0 nomodify notrap
And protect your server from outside influence with:
server 0.rhel.pool.ntp.org burst iburst
restrict 0.rhel.pool.ntp.org mask 255.255.255.255 nomodify notrap noquery
In /etc/ntp/ntpservers you list your outside sources (or inside for the
/etc/sysconfig/ntpd controls updating your hardware clock:
# Set to 'yes' to sync hw clock after successful ntpdate
Anyway for your clients to get time, you have to allow udp/tcp port 123
in your firewall and set up /etc/ntp.conf.
(this message is a little scattered, as I am suppose to be listing to
this presentation on comment resolution on the 802.15.4g ballot. *boring).
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To fit this in a bit with your set up. Have your 192.168.1.100 box be your main time server. Have .101 be secondary, getting time from .100. Then each of the respective 10.5/6 boxes can get their time from their attached server.
Robert's info can be modified for this...John
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