ntp

ntp

[Luca Ferrari]

Hi,
I'd like to set up a ntp server and several clients connected to the server 
itself. Unluckily I'm unable to find documentation on-line, or better I 
cannot understand what I've found. Briefly here there's what I've done:
- on the server:
_ installed ntp
_ configuration file /etc/ntp.conf contains the line 
server 127.0.0.1
_ I launch ntp and query it:
ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 localhost       0.0.0.0          0 l    -   64    0    0.000    0.000 4000.00


- clients:
_ set the ntp.conf file to point to the server:
server ntpserver
_ launch ntp but I get the message (in the warnings) that there is no service 
running at the server
_ try with ntpdate but I cannot get the time from the server.

What's wrong with this small configuration?

Thanks,
Luca

-- 
Luca Ferrari,
fluca1978@virgilio.it

Re: ntp

[Jeffrey Morse]

Here is a very good resource for NTP configuration along with many other
helpful Linux configurations.

* On [02-26-2004 09:08 +0100] Luca Ferrari <fluca1978@virgilio.it> wrote:
> Hi,
> I'd like to set up a ntp server and several clients connected to the server 
> itself. Unluckily I'm unable to find documentation on-line, or better I 
> cannot understand what I've found. Briefly here there's what I've done:
> - on the server:
> _ installed ntp
> _ configuration file /etc/ntp.conf contains the line 
> server 127.0.0.1
> _ I launch ntp and query it:
> ntpq -p
>      remote           refid      st t when poll reach   delay   offset  jitter
> ==============================================================================
>  localhost       0.0.0.0          0 l    -   64    0    0.000    0.000 4000.00
> 
> 
> - clients:
> _ set the ntp.conf file to point to the server:
> server ntpserver
> _ launch ntp but I get the message (in the warnings) that there is no service 
> running at the server
> _ try with ntpdate but I cannot get the time from the server.
> 
> What's wrong with this small configuration?
> 
> Thanks,
> Luca
> 
> -- 
> Luca Ferrari,
> fluca1978@virgilio.it
> -
> To unsubscribe from this list: send the line "unsubscribe linux-admin" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: ntp

[Jeffrey Morse]

OOPS, sorry about that, here is the link:

http://www.siliconvalleyccie.com/index.htm

Jeff

* On [02-26-2004 03:09 -0600] Jeffrey Morse <jmorse@m4cc.com> wrote:
> Here is a very good resource for NTP configuration along with many other
> helpful Linux configurations.
> 
> * On [02-26-2004 09:08 +0100] Luca Ferrari <fluca1978@virgilio.it> wrote:
> > Hi,
> > I'd like to set up a ntp server and several clients connected to the server 
> > itself. Unluckily I'm unable to find documentation on-line, or better I 
> > cannot understand what I've found. Briefly here there's what I've done:
> > - on the server:
> > _ installed ntp
> > _ configuration file /etc/ntp.conf contains the line 
> > server 127.0.0.1
> > _ I launch ntp and query it:
> > ntpq -p
> >      remote           refid      st t when poll reach   delay   offset  jitter
> > ==============================================================================
> >  localhost       0.0.0.0          0 l    -   64    0    0.000    0.000 4000.00
> > 
> > 
> > - clients:
> > _ set the ntp.conf file to point to the server:
> > server ntpserver
> > _ launch ntp but I get the message (in the warnings) that there is no service 
> > running at the server
> > _ try with ntpdate but I cannot get the time from the server.
> > 
> > What's wrong with this small configuration?
> > 
> > Thanks,
> > Luca
> > 
> > -- 
> > Luca Ferrari,
> > fluca1978@virgilio.it
> > -
> > To unsubscribe from this list: send the line "unsubscribe linux-admin" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> -
> To unsubscribe from this list: send the line "unsubscribe linux-admin" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: ntp

[terry white]

on "2-26-2004" "Luca Ferrari" writ:

: I'd like to set up a ntp server and several clients connected to the server

: _ configuration file /etc/ntp.conf contains the line
: server 127.0.0.1

... ciao:

    first, to be a server, you have to be a client of one, OR, have
access to accurate time information; typically via 'radio' if no access
to net based time servers available to you.  so, line similar to the
following should appear:

	"server  time.nist.gov"
	"server  time-a.timefreq.bldrdoc.gov"

these are the 'servers' i poll for time information.  when you use the
'loopback' address, you're asking 'yourself' what time it is.

    instead of being a 'time server' per se, remote systems use 'rdate'
in a cron event to keep 'hourly accurate' time.


: ntpq -p
:      remote           refid      st t when poll reach   delay   offset  jitter
: ==============================================================================
:  localhost       0.0.0.0          0 l    -   64    0    0.000    0.000 4000.00

    on this system:

[ root  ] ~  # ntpq -p
     remote      refid     st t when poll reach   delay   offset  jitter
==============================================================================
 time.nist.gov   .ACTS.     1 u 1409 1024   16   86.885   -5.531  3.542
*time-A.timefreq .ACTS.     1 u  318 1024  377   95.454   -5.127  5.316

    hope that helps ...


-- 
... i'm a man, but i can change,
    if i have to , i guess ...

Re: ntp

[Milan P. Stanic]

On Thu, Feb 26, 2004 at 01:24:25AM -0800, terry white wrote:
>     first, to be a server, you have to be a client of one, OR, have
> access to accurate time information; typically via 'radio' if no access
> to net based time servers available to you.  so, line similar to the
> following should appear:
> 
> 	"server  time.nist.gov"
> 	"server  time-a.timefreq.bldrdoc.gov"
> 
> these are the 'servers' i poll for time information.  when you use the
> 'loopback' address, you're asking 'yourself' what time it is.
 
New (and preferred way) is to use pool.ntp.org as servers.

Info's are on the http://pool.ntp.org/ IIRC.

Re: ntp

[Milan P. Stanic]

On Thu, Feb 26, 2004 at 10:47:15AM +0100, Milan P. Stanic wrote:
> On Thu, Feb 26, 2004 at 01:24:25AM -0800, terry white wrote:
> >     first, to be a server, you have to be a client of one, OR, have
> > access to accurate time information; typically via 'radio' if no access
> > to net based time servers available to you.  so, line similar to the
> > following should appear:
> > 
> > 	"server  time.nist.gov"
> > 	"server  time-a.timefreq.bldrdoc.gov"
> > 
> > these are the 'servers' i poll for time information.  when you use the
> > 'loopback' address, you're asking 'yourself' what time it is.
>  
> New (and preferred way) is to use pool.ntp.org as servers.
> 
> Info's are on the http://pool.ntp.org/ IIRC.

Sorry, I was wrong. It is on the http://fortytwo.ch/time/

NTP

[Steve Comfort]

Hi all,

Could someone tell me what rules I need in order to enable NTP?

Best regards
Steve

Re: NTP

[Gavin Hamill]

On Friday 02 July 2004 11:57, Steve Comfort wrote:
> Hi all,
>
> Could someone tell me what rules I need in order to enable NTP?

Simply allow incoming UDP on port 123. The 'normal' way is for both the source 
and destination ports to be 123, but it is common (esp. with debugging) for 
the source port to be >1024.

Cheers,
Gavin.

Re: NTP

[Antony Stone]

On Friday 02 July 2004 11:57 am, Steve Comfort wrote:

> Hi all,
>
> Could someone tell me what rules I need in order to enable NTP?

NTP uses UDP port 123.

What rules you need depends on what you're trying to do - run an NTP server 
(allow UDP 123 in the INPUT chain), access an NTP server (allow UDP 123 in 
the OUTPUT chain), or allow clients and servers to talk to each other through 
a router (allow UDP 123 through the FORWARD chain).

If in doubt, add a LOG rule, try using the protocol, and see what gets logged 
- that will tell you what sort of packets you need to ACCEPT instead.

Regards,

Antony.

-- 
Software development can be quick, high quality, or low cost.

The customer gets to pick any two out of three.

                                                     Please reply to the list;
                                                           please don't CC me.

RE: NTP

[Hudson Delbert J Contr 61 CS/SCBN]

do not i repeat...do not allow inbound ntp with a source port above the root
ports.



####################################
# delbert.hudson@losangeles.af.mil #
#        61cs/scbn, 3-0182         #
####################################


-----Original Message-----
From: netfilter-admin@lists.netfilter.org
[mailto:netfilter-admin@lists.netfilter.org]On Behalf Of Gavin Hamill
Sent: Friday, July 02, 2004 4:07 AM
To: netfilter@lists.netfilter.org
Subject: Re: NTP


On Friday 02 July 2004 11:57, Steve Comfort wrote:
> Hi all,
>
> Could someone tell me what rules I need in order to enable NTP?

Simply allow incoming UDP on port 123. The 'normal' way is for both the
source 
and destination ports to be 123, but it is common (esp. with debugging) for 
the source port to be >1024.

Cheers,
Gavin.

Re: NTP

[Antony Stone]

On Friday 02 July 2004 5:28 pm, Hudson Delbert J Contr 61 CS/SCBN wrote:

> do not i repeat...do not allow inbound ntp with a source port above the
> root ports.

Why not?   What difference does the client's source port make?

Antony.

> -----Original Message-----
> From: netfilter-admin@lists.netfilter.org
> [mailto:netfilter-admin@lists.netfilter.org]On Behalf Of Gavin Hamill
> Sent: Friday, July 02, 2004 4:07 AM
> To: netfilter@lists.netfilter.org
> Subject: Re: NTP
>
> On Friday 02 July 2004 11:57, Steve Comfort wrote:
> > Hi all,
> >
> > Could someone tell me what rules I need in order to enable NTP?
>
> Simply allow incoming UDP on port 123. The 'normal' way is for both the
> source
> and destination ports to be 123, but it is common (esp. with debugging) for
> the source port to be >1024.
>
> Cheers,
> Gavin.

-- 
There's no such thing as bad weather - only the wrong clothes.

 - Billy Connolly

                                                     Please reply to the list;
                                                           please don't CC me.

RE: NTP

[Mark E. Donaldson]

 

-----Original Message-----
From: netfilter-admin@lists.netfilter.org
[mailto:netfilter-admin@lists.netfilter.org] On Behalf Of Antony Stone
Sent: Friday, July 02, 2004 11:07 AM
To: netfilter@lists.netfilter.org
Subject: Re: NTP

On Friday 02 July 2004 5:28 pm, Hudson Delbert J Contr 61 CS/SCBN wrote:

> do not i repeat...do not allow inbound ntp with a source port above 
> the root ports.

Why not?   What difference does the client's source port make?

Antony.

Yes - I'm quite curious about this too as the protocol "normally" acts as
follows:
Client > 1023 -> Server 123
Server 123 -> Client > 1023
Server 123 -> Server 123

Re: NTP

[Gavin Hamill]

On Friday 02 July 2004 17:28, Hudson Delbert J Contr 61 CS/SCBN wrote:
> do not i repeat...do not allow inbound ntp with a source port above the
> root ports.

Hi Delbert - would you mind expanding on this to include the reasons why?

Cheers,
Gavin.

Re: NTP

[Antony Stone]

On Friday 02 July 2004 5:28 pm, Hudson Delbert J Contr 61 CS/SCBN wrote:

> do not i repeat...do not allow inbound ntp with a source port above the
> root ports.

Was there ever a follow-up reply about this?

Several people asked for more details, a bit of explanation, or a reference to 
find out more - I didn't see anything back again from Hudson Delbert J Contr?

I'd be very interested to know the reason for the recommendation.

Regards,

Antony.

-- 
Perfection in design is achieved not when there is nothing left to add, but 
rather when there is nothing left to take away.

 - Antoine de Saint-Exupery

                                                     Please reply to the list;
                                                           please don't CC me.

RE: NTP

[Rob Sterenborg]

> > do not i repeat...do not allow inbound ntp with a source port above 
> > the root ports.
> 
> Was there ever a follow-up reply about this?

Not according to my mail history.
Maybe he went on holliday and therefore cannot elaborate on this ..?


Gr,
Rob

ntp

[zhangxiliang]

When i start the ntp service successful on server, the client must ntpdate
with the server after waiting a moment.
The moment may be 3~5 minutes, or it may be 10~15 minutes. I don't know why
it happens?

Regards
Zhang Xiliang
--------------------------------------------------
Zhang Xiliang
Development Dept.I
Nanjing Fujitsu Nanda Software Tech. Co., Ltd.(FNST)
8/F., Civil Defense Building, No.189 Guangzhou Road,
Nanjing, 210029, China
TEL: +86+25-86630566-851
COINS: 79955-851
FAX: +86+25-83317685
MAIL:zhangxiliang@nanjing-fnst.com
--------------------------------------------------

Re: ntp

[Matti Aarnio]

On Fri, Feb 02, 2007 at 04:47:26PM +0800, zhangxiliang wrote:
> When i start the ntp service successful on server, the client must
> ntpdate with the server after waiting a moment.
> The moment may be 3~5 minutes, or it may be 10~15 minutes. I don't
> know why it happens?

The  ntp server  takes several external clock comparisons to know its
local running environments (hosts) clock behaviour.

Before it knows that, it has no real knowledge of what the time is,
and it won't report anything out.

In my environments I have couple local machines (usually doing
something else too) assigned as network local NTP servers, and
all other machines refer to them.


> Regards
> Zhang Xiliang
> MAIL:zhangxiliang@nanjing-fnst.com

/Matti Aarnio

Re: ntp

[zhangxiliang]

Hello.
When I use the ntpd service, I see if I use the client attempt to connect 
the server repeat before the server is ready, the ntpd on server can not be 
ready all the times.

Sometimes the waiting time maybe very long.

----- Original Message ----- 
From: "Matti Aarnio" <matti.aarnio@zmailer.org>
To: "zhangxiliang" <zhangxiliang@nanjing-fnst.com>
Cc: "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>
Sent: Friday, February 02, 2007 5:10 PM
Subject: Re: ntp


> On Fri, Feb 02, 2007 at 04:47:26PM +0800, zhangxiliang wrote:
>> When i start the ntp service successful on server, the client must
>> ntpdate with the server after waiting a moment.
>> The moment may be 3~5 minutes, or it may be 10~15 minutes. I don't
>> know why it happens?
>
> The  ntp server  takes several external clock comparisons to know its
> local running environments (hosts) clock behaviour.
>
> Before it knows that, it has no real knowledge of what the time is,
> and it won't report anything out.
>
> In my environments I have couple local machines (usually doing
> something else too) assigned as network local NTP servers, and
> all other machines refer to them.
>
>
>> Regards
>> Zhang Xiliang
>> MAIL:zhangxiliang@nanjing-fnst.com
>
> /Matti Aarnio
> 

RE: ntp

[David Schwartz]

> Hello.
> When I use the ntpd service, I see if I use the client attempt to connect
> the server repeat before the server is ready, the ntpd on server
> can not be
> ready all the times.
>
> Sometimes the waiting time maybe very long.

Sounds like NTP is the wrong tool for the job. NTP is specifically designed
to synchronize clocks with high accuracy to timing sources traceable to UTC.
It requires stable servers in order to do that. There are any number of
other time settings tools that don't try to actually synchronize clocks.

DS

RE: ntp

[David Schwartz]

> When i start the ntp service successful on server, the client must ntpdate
> with the server after waiting a moment.
> The moment may be 3~5 minutes, or it may be 10~15 minutes. I
> don't know why
> it happens?

Two clocks cannot be synchronized instantaneously. It takes time to compare
the two clocks and adjust so that they stay in sync. A client will not
accept a date from an NTP server whose clock is not synchronized -- why
should it?

Imagine this -- you have a clock you do not trust. You ask a clock you do
trust what time it is, and it tells you it is 10:00. A bit later, I ask you
what time it is. Your clock says 10:12. Can you trust that time? Your clock
may be fast, it may be slow. You don't know. Until you check the clock you
trust a few times and confirm both clocks are flowing at the same rate, you
cannot tell the client what time it is when it asks you.

DS

NTP

[Anicic Damir (PSI)]

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Hi!

I just realised that ntpd + ntpdate is not part of Yocto 2.1

I found http://layers.openembedded.org/layerindex/recipe/2299/

but how to get it?


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Re: NTP

[piotr.lewicki]

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On 17.06.2016 08:33, Anicic Damir (PSI) wrote:
> Hi!
>
> I just realised that ntpd + ntpdate is not part of Yocto 2.1
What do you mean by "not part of Yocto"?
>
> I found http://layers.openembedded.org/layerindex/recipe/2299/ 
> <http://layers.openembedded.org/layerindex/recipe/2299/>
>
> but how to get it?
You need to add a layer "meta-networking" which is a part of 
"meta-openembedded" and the recipe is there at 
meta-openembedded/meta-networking/recipes-support/ntp
Link: http://cgit.openembedded.org/meta-openembedded/

Best Regards
Piotr Lewicki

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Re: NTP

[Anicic Damir (PSI)]

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I am new to Yocto, so please explain a bit more.

All I have done is:
  git clone -b krogoth git://git.yoctoproject.org/poky.git

How do I now add layers ?

Or can I somehow clone Yocto 2.1 with all layers ?

Damir


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Re: NTP

[piotr.lewicki]

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> I am new to Yocto, so please explain a bit more.
Not all of the recipes can be found in poky layers.
You can use multiple layers together to be able to access more recipes 
(and features like bbclasses, etc.).
You will find more info in the manual.
>
> All I have done is:
>   git clone -b krogoth git://git.yoctoproject.org/poky.git
>
> How do I now add layers ?
http://www.yoctoproject.org/docs/2.1/dev-manual/dev-manual.html#enabling-your-layer
You will find the whole manual quite useful.
>
> Or can I somehow clone Yocto 2.1 with all layers ?
I don't think that's possible.
>
> Damir
>

Best regards,
Piotr Lewicki

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Re: NTP

[akuster]

On 06/16/2016 11:33 PM, Anicic Damir (PSI) wrote:
> Hi!
> 
> I just realised that ntpd + ntpdate is not part of Yocto 2.1

ntpdate is in the ntpdate package and ntpd is in the ntp package.

The ntp recipe is in meta-openembedded/meta-networking

you will need to append these to your image install.

- armin
> 
> I found http://layers.openembedded.org/layerindex/recipe/2299/
> 
> but how to get it?
> 
> 
> 
> 

Re: NTP

[Jussi Kukkonen]

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On 17 June 2016 at 09:33, Anicic Damir (PSI) <damir.anicic@psi.ch> wrote:
>
> Hi!
>
> I just realised that ntpd + ntpdate is not part of Yocto 2.1
>
> I found http://layers.openembedded.org/layerindex/recipe/2299/
>
> but how to get it?

Note that you do not need ntpd or extra layers for ntp client functionality
if you use systemd. See
https://www.freedesktop.org/software/systemd/man/systemd-timesyncd.service.html
and https://www.freedesktop.org/software/systemd/man/timedatectl.html. I'm
not sure what the default NTP setting is, you may have to enable it.

- Jussi

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