What happens if ntp server unavailable at start up? - NTP

This is a discussion on What happens if ntp server unavailable at start up? - NTP ; A question has arisen in another group-- What happens if, when ntp starts up, the remoter server is unavailable ( eg no DNS or no connection)? This is highly likely to be the case for a laptop for example, where ...

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  1. What happens if ntp server unavailable at start up?

    A question has arisen in another group-- What happens if, when ntp starts
    up, the remoter server is unavailable ( eg no DNS or no connection)?
    This is highly likely to be the case for a laptop for example, where the
    connection with the local network is only brought up by the user after a
    while, or on wakeup from a power outage when the net may be unstable or the
    router be out when ntp comes up.

    If a server disappears in a running ntp, ntp keeps trying, backing off on
    the poll interval after a while. But what does ntp do if on the first try
    to a server, there is no response, or if the dns is down. Does it forever
    scrub that server? (that seems to be what happnes-- if so why?) or does it
    do the same thing as if the server disappears after a while (keep trying
    with increasing poll intervals)?

    I notice that there is a keyword dynamic which is not yet implimented but
    which seems to imply the second option.

    Also what happens to ntpd if it has no servers whatsoever, not even a local
    one? Does it keep running, doing nothing, or does it exit?



  2. Re: What happens if ntp server unavailable at start up?

    On 2008-09-11, Bill Unruh wrote:

    > A question has arisen in another group-- What happens if, when ntp starts
    > up, the remoter server is unavailable ( eg no DNS or no connection)?
    > This is highly likely to be the case for a laptop for example, where the
    > connection with the local network is only brought up by the user after a
    > while, or on wakeup from a power outage when the net may be unstable or the
    > router be out when ntp comes up.


    As of 4.2.4p5 ntpd does the right thing in these situations. Here's an
    extract from the stable release ChangeLog:

    (4.2.4p5) 2008/08/17 Released by Harlan Stenn

    * [Bug 841] Obsolete the "dynamic" keyword and make deferred
    binding to local interfaces the default.
    Emit a warning if that keyword is used for configuration.

    The complete ChangeLog is at http://archive.ntp.org/ntp4/ChangeLog-stable

    --
    Steve Kostecke
    NTP Public Services Project - http://support.ntp.org/

  3. Re: What happens if ntp server unavailable at start up?

    Bill,

    Bill Unruh wrote:
    > A question has arisen in another group-- What happens if, when ntp starts
    > up, the remoter server is unavailable ( eg no DNS or no connection)?
    > This is highly likely to be the case for a laptop for example, where the
    > connection with the local network is only brought up by the user after a
    > while, or on wakeup from a power outage when the net may be unstable or
    > the router be out when ntp comes up.
    >
    > If a server disappears in a running ntp, ntp keeps trying, backing off on
    > the poll interval after a while. But what does ntp do if on the first try
    > to a server, there is no response, or if the dns is down. Does it forever
    > scrub that server? (that seems to be what happnes-- if so why?) or does it
    > do the same thing as if the server disappears after a while (keep trying
    > with increasing poll intervals)?
    >
    > I notice that there is a keyword dynamic which is not yet implimented but
    > which seems to imply the second option.


    The keywaord "dynamic" had been introduced IIRC in 4.2.4. It lets ntpd retry
    if a server can not be reached initially.

    However, since the behaviour with the "dynamic" keyword is what users would
    normally expect ntpd to do I have proposed to make the "dynamic" behaviour
    the default and obsolete the "dynamic" keyword. This has been done in
    current ntp-dev and int ntp-stable 4.2.4p5.

    For details see:
    https://support.ntp.org/bugs/show_bug.cgi?id=841
    https://support.ntp.org/bugs/show_bug.cgi?id=987

    > Also what happens to ntpd if it has no servers whatsoever, not even a
    > local one? Does it keep running, doing nothing, or does it exit?


    What do you mean by "has no servers"? "Has no servers configured", or "has
    no servers reachable"? In the latter case ntpd 4.2.4p5 just retries until a
    network interface becomes available.

    Martin
    --
    Martin Burnicki

    Meinberg Funkuhren
    Bad Pyrmont
    Germany

  4. Re: What happens if ntp server unavailable at start up?

    Steve Kostecke writes:

    >On 2008-09-11, Bill Unruh wrote:


    >> A question has arisen in another group-- What happens if, when ntp starts
    >> up, the remoter server is unavailable ( eg no DNS or no connection)?
    >> This is highly likely to be the case for a laptop for example, where the
    >> connection with the local network is only brought up by the user after a
    >> while, or on wakeup from a power outage when the net may be unstable or the
    >> router be out when ntp comes up.


    >As of 4.2.4p5 ntpd does the right thing in these situations. Here's an
    >extract from the stable release ChangeLog:


    >(4.2.4p5) 2008/08/17 Released by Harlan Stenn


    >* [Bug 841] Obsolete the "dynamic" keyword and make deferred
    > binding to local interfaces the default.
    > Emit a warning if that keyword is used for configuration.


    "deferred binding to local interfaces" means what? If my server is a
    pool.ntp server, but my gateway is down when I boot up, will it eventually
    bind to pool? Or just say-- the hell with it? What counts as "local"?

    Did the dynamic keyword ever work? The web docs say that it is not yet
    implimented.


    >The complete ChangeLog is at http://archive.ntp.org/ntp4/ChangeLog-stable


    >--
    >Steve Kostecke
    >NTP Public Services Project - http://support.ntp.org/


  5. Re: What happens if ntp server unavailable at start up?

    Martin Burnicki writes:

    >Bill,


    >Bill Unruh wrote:
    >> A question has arisen in another group-- What happens if, when ntp starts
    >> up, the remoter server is unavailable ( eg no DNS or no connection)?
    >> This is highly likely to be the case for a laptop for example, where the
    >> connection with the local network is only brought up by the user after a
    >> while, or on wakeup from a power outage when the net may be unstable or
    >> the router be out when ntp comes up.
    >>
    >> If a server disappears in a running ntp, ntp keeps trying, backing off on
    >> the poll interval after a while. But what does ntp do if on the first try
    >> to a server, there is no response, or if the dns is down. Does it forever
    >> scrub that server? (that seems to be what happnes-- if so why?) or does it
    >> do the same thing as if the server disappears after a while (keep trying
    >> with increasing poll intervals)?
    >>
    >> I notice that there is a keyword dynamic which is not yet implimented but
    >> which seems to imply the second option.


    >The keywaord "dynamic" had been introduced IIRC in 4.2.4. It lets ntpd retry
    >if a server can not be reached initially.


    >However, since the behaviour with the "dynamic" keyword is what users would
    >normally expect ntpd to do I have proposed to make the "dynamic" behaviour
    >the default and obsolete the "dynamic" keyword. This has been done in
    >current ntp-dev and int ntp-stable 4.2.4p5.


    >For details see:
    >https://support.ntp.org/bugs/show_bug.cgi?id=841


    That one seems have degenerated into a slangfest about how bugs should be
    handled. It is not at all clear from that discussion that the bug has in
    fact been fixed.

    >https://support.ntp.org/bugs/show_bug.cgi?id=987


    >> Also what happens to ntpd if it has no servers whatsoever, not even a
    >> local one? Does it keep running, doing nothing, or does it exit?


    >What do you mean by "has no servers"? "Has no servers configured", or "has
    >no servers reachable"? In the latter case ntpd 4.2.4p5 just retries until a
    >network interface becomes available.


    Sounds great. So, let me say I have pool.ntp.org as a server. when my
    system comes up (a desktop) the network interface is there, but the dns
    server is still dead, and the gateway is still dead. Ie, no address for
    pool can be gotten from dns. Does the system keep trying or does it give up
    on that server?


    >Martin
    >--
    >Martin Burnicki


    >Meinberg Funkuhren
    >Bad Pyrmont
    >Germany


  6. Re: What happens if ntp server unavailable at start up?

    On Sep 12, 8:31*am, Unruh wrote:
    >
    > Sounds great. So, let me say I have pool.ntp.org as a server. when my
    > system comes up (a desktop) the network interface is there, but the dns
    > server is still dead, and the gateway is still dead. Ie, no address for
    > pool can be gotten from dns. Does the system keep trying or does it give up
    > on that server?


    Similarly, if a connection is dropped, will NTP query the DNS server
    about the IP of a specified server again or will it binds to an IP
    address and never give it up?

    TIA

  7. Re: What happens if ntp server unavailable at start up?

    On 2008-09-12, Evandro Menezes wrote:

    > On Sep 12, 8:31*am, Unruh wrote:
    >
    >> Sounds great. So, let me say I have pool.ntp.org as a server. when
    >> my system comes up (a desktop) the network interface is there, but
    >> the dns server is still dead, and the gateway is still dead. Ie, no
    >> address for pool can be gotten from dns. Does the system keep trying
    >> or does it give up on that server?


    As of 4.2.4p5 it will keep retrying without additional configuration.

    > Similarly, if a connection is dropped, will NTP query the DNS server
    > about the IP of a specified server again or will it binds to an IP
    > address and never give it up?


    Not yet.

    --
    Steve Kostecke
    NTP Public Services Project - http://support.ntp.org/

  8. Re: What happens if ntp server unavailable at start up?

    >>> In article , Unruh writes:

    Unruh> Steve Kostecke writes:
    >> On 2008-09-11, Bill Unruh wrote:


    >>> A question has arisen in another group-- What happens if, when ntp
    >>> starts up, the remoter server is unavailable ( eg no DNS or no
    >>> connection)?


    I think, and I could be wrong:

    - if we can't reach DNS, we keep trying until we do
    - if we get an authoritiative "That site doesn't exist" we move on
    - if the interface is unavailable it will be added to the list when
    it comes up.

    If we know the IP of the remote machine, it is added to the association
    list.

    >> As of 4.2.4p5 ntpd does the right thing in these situations. Here's an
    >> extract from the stable release ChangeLog:
    >> (4.2.4p5) 2008/08/17 Released by Harlan Stenn
    >> * [Bug 841] Obsolete the "dynamic" keyword and make deferred binding to
    >> local interfaces the default. Emit a warning if that keyword is used for
    >> configuration.


    Unruh> "deferred binding to local interfaces" means what? If my server is a
    Unruh> pool.ntp server, but my gateway is down when I boot up, will it
    Unruh> eventually bind to pool? Or just say-- the hell with it? What counts
    Unruh> as "local"?

    A local interface is a NIC on the local machine.

    There are a bunch of pieces here, DNS, NICs, and routing.

    Unruh> Did the dynamic keyword ever work? The web docs say that it is not
    Unruh> yet implimented.

    I'm pretty sure it works - what documentation says it doesn't?

    --
    Harlan Stenn
    http://ntpforum.isc.org - be a member!

  9. Re: What happens if ntp server unavailable at start up?

    Harlan Stenn writes:

    >>>> In article , Unruh writes:


    >Unruh> Steve Kostecke writes:
    >>> On 2008-09-11, Bill Unruh wrote:


    >>>> A question has arisen in another group-- What happens if, when ntp
    >>>> starts up, the remoter server is unavailable ( eg no DNS or no
    >>>> connection)?


    >I think, and I could be wrong:


    >- if we can't reach DNS, we keep trying until we do
    >- if we get an authoritiative "That site doesn't exist" we move on
    >- if the interface is unavailable it will be added to the list when
    > it comes up.


    >If we know the IP of the remote machine, it is added to the association
    >list.


    >>> As of 4.2.4p5 ntpd does the right thing in these situations. Here's an
    >>> extract from the stable release ChangeLog:
    >>> (4.2.4p5) 2008/08/17 Released by Harlan Stenn
    >>> * [Bug 841] Obsolete the "dynamic" keyword and make deferred binding to
    >>> local interfaces the default. Emit a warning if that keyword is used for
    >>> configuration.


    >Unruh> "deferred binding to local interfaces" means what? If my server is a
    >Unruh> pool.ntp server, but my gateway is down when I boot up, will it
    >Unruh> eventually bind to pool? Or just say-- the hell with it? What counts
    >Unruh> as "local"?


    >A local interface is a NIC on the local machine.


    >There are a bunch of pieces here, DNS, NICs, and routing.


    >Unruh> Did the dynamic keyword ever work? The web docs say that it is not
    >Unruh> yet implimented.


    >I'm pretty sure it works - what documentation says it doesn't?


    Some document on ntp.org describing the options in the ntp.conf file.
    I do not want to look for it again-- the docs are incredibly hard to
    search-- one of the problems with making them into an infinite number of
    web pages. So I guess dynamic went from not implimented to deprecated with
    only a brief stop of in use in between.


    >--
    >Harlan Stenn
    >http://ntpforum.isc.org - be a member!


  10. Re: What happens if ntp server unavailable at start up?

    Evandro Menezes wrote:
    > On Sep 12, 8:31 am, Unruh wrote:
    >> Sounds great. So, let me say I have pool.ntp.org as a server. when my
    >> system comes up (a desktop) the network interface is there, but the dns
    >> server is still dead, and the gateway is still dead. Ie, no address for
    >> pool can be gotten from dns. Does the system keep trying or does it give up
    >> on that server?

    >
    > Similarly, if a connection is dropped, will NTP query the DNS server
    > about the IP of a specified server again or will it binds to an IP
    > address and never give it up?
    >


    There is NO "connection"!! UDP, which is what NTP uses is a
    connectionless protocol. If a client receives no response to a query,
    it is supposed to wait and try again, double the wait time and try
    again, etc. I believe that a conforming implementation is supposed keep
    doubling the retry time until it reaches 1024 seconds.

  11. Re: What happens if ntp server unavailable at start up?

    "Richard B. Gilbert" writes:

    >Evandro Menezes wrote:
    >> On Sep 12, 8:31 am, Unruh wrote:
    >>> Sounds great. So, let me say I have pool.ntp.org as a server. when my
    >>> system comes up (a desktop) the network interface is there, but the dns
    >>> server is still dead, and the gateway is still dead. Ie, no address for
    >>> pool can be gotten from dns. Does the system keep trying or does it give up
    >>> on that server?

    >>
    >> Similarly, if a connection is dropped, will NTP query the DNS server
    >> about the IP of a specified server again or will it binds to an IP
    >> address and never give it up?
    >>



    It does not query the dns server each time it sends out a packet. It
    remembers.
    By connection I think he means tat association of name-IP and sending out
    and receiving back packets.

    So by "connection dropped" I believe he means "send out a query packet and
    receive no reply".


    >There is NO "connection"!! UDP, which is what NTP uses is a
    >connectionless protocol. If a client receives no response to a query,
    >it is supposed to wait and try again, double the wait time and try
    >again, etc. I believe that a conforming implementation is supposed keep
    >doubling the retry time until it reaches 1024 seconds.


  12. Re: What happens if ntp server unavailable at start up?

    In article ,
    Unruh wrote:

    > Harlan Stenn writes:

    [snip]
    >
    > >Unruh> Did the dynamic keyword ever work? The web docs say that it is not
    > >Unruh> yet implimented.

    >
    > >I'm pretty sure it works - what documentation says it doesn't?

    >
    > Some document on ntp.org describing the options in the ntp.conf file.
    > I do not want to look for it again-- the docs are incredibly hard to
    > search-- one of the problems with making them into an infinite number of
    > web pages.


    What I find useful is to use google with a "site:udel.edu" qualifier.

    It would help if the docs entire tree were under ntp.org though.

    Joe Gwinn

  13. Re: What happens if ntp server unavailable at start up?

    >>> In article , Unruh writes:

    Unruh> Did the dynamic keyword ever work? The web docs say that it is not
    Unruh> yet implimented.

    Harlan> I'm pretty sure it works - what documentation says it doesn't?

    Unruh> Some document on ntp.org describing the options in the ntp.conf file.
    Unruh> I do not want to look for it again-- the docs are incredibly hard to
    Unruh> search-- one of the problems with making them into an infinite number
    Unruh> of web pages.

    Try http://doc.ntp.org .

    Unruh> So I guess dynamic went from not implimented to
    Unruh> deprecated with only a brief stop of in use in between.

    No, it went from implemented as an option to implemented by default.

    --
    Harlan Stenn
    http://ntpforum.isc.org - be a member!

  14. Re: What happens if ntp server unavailable at start up?

    On 2008-09-13, Joseph Gwinn wrote:

    > Unruh wrote:
    >
    >> Harlan Stenn writes:
    >>
    >> >Unruh> Did the dynamic keyword ever work? The web docs say that it
    >> >Unruh> is not yet implimented.

    >>
    >> >I'm pretty sure it works - what documentation says it doesn't?

    >>
    >> Some document on ntp.org describing the options in the ntp.conf file.
    >> I do not want to look for it again-- the docs are incredibly hard to
    >> search-- one of the problems with making them into an infinite number
    >> of web pages.

    >
    > What I find useful is to use google with a "site:udel.edu" qualifier.
    >
    > It would help if the docs entire tree were under ntp.org though.


    The documentation at http://www.eecis.udel.edu/~mills/ntp/html/ is the
    documentation for the current development snapshot of The NTP Reference
    Implementation (from www.ntp.org). This documentation may be correct
    for stable releases.

    An archive of documentation for stable releases of The NTP Reference
    Implementation is located at http://doc.ntp.org/. This archive provides
    search capabilities powered by ht://dig.

    The documentation contained in this archive is presented in its original
    form with the exception of the addition of a site-wide searching /
    navigation tool-bar and an HTML wrapper, which includes the tool bar,
    for plain-text files and directory listings.

    If you wish to use Google to search the on-line stable release
    documentation use "site:doc.ntp.org" in your search arguments.

    --
    Steve Kostecke
    NTP Public Services Project - http://support.ntp.org/

  15. Re: What happens if ntp server unavailable at start up?

    Harlan Stenn writes:

    >>>> In article , Unruh writes:


    >Unruh> Did the dynamic keyword ever work? The web docs say that it is not
    >Unruh> yet implimented.


    >Harlan> I'm pretty sure it works - what documentation says it doesn't?


    http://www.eecis.udel.edu/~mills/ntp/html/confopt.html

    dynamic
    Allows a server/peer to be configured even if it is not reachable at
    configuration time. It is assumed that at some point in the future the
    network environment changes so that this server/peer can be reached. This
    option is useful to configure servers/peers on mobile systems with
    intermittent network access (e.g. wlan clients). Note: the current
    implemenation does not support this option.

    See that last sentence?



    >Unruh> Some document on ntp.org describing the options in the ntp.conf file.
    >Unruh> I do not want to look for it again-- the docs are incredibly hard to
    >Unruh> search-- one of the problems with making them into an infinite number
    >Unruh> of web pages.


    >Try http://doc.ntp.org .


    >Unruh> So I guess dynamic went from not implimented to
    >Unruh> deprecated with only a brief stop of in use in between.


    >No, it went from implemented as an option to implemented by default.


    According to the above it went from not implimented to implimented by
    default.
    And the OPTION was deprecated because it was implimented by default.
    It is no longer an option.





    >--
    >Harlan Stenn
    >http://ntpforum.isc.org - be a member!


  16. Re: What happens if ntp server unavailable at start up?

    Steve Kostecke writes:

    >On 2008-09-13, Joseph Gwinn wrote:


    >> Unruh wrote:
    >>
    >>> Harlan Stenn writes:
    >>>
    >>> >Unruh> Did the dynamic keyword ever work? The web docs say that it
    >>> >Unruh> is not yet implimented.
    >>>
    >>> >I'm pretty sure it works - what documentation says it doesn't?
    >>>
    >>> Some document on ntp.org describing the options in the ntp.conf file.
    >>> I do not want to look for it again-- the docs are incredibly hard to
    >>> search-- one of the problems with making them into an infinite number
    >>> of web pages.

    >>
    >> What I find useful is to use google with a "site:udel.edu" qualifier.
    >>
    >> It would help if the docs entire tree were under ntp.org though.


    >The documentation at http://www.eecis.udel.edu/~mills/ntp/html/ is the
    >documentation for the current development snapshot of The NTP Reference
    >Implementation (from www.ntp.org). This documentation may be correct
    >for stable releases.


    >An archive of documentation for stable releases of The NTP Reference
    >Implementation is located at http://doc.ntp.org/. This archive provides
    >search capabilities powered by ht://dig.


    >The documentation contained in this archive is presented in its original
    >form with the exception of the addition of a site-wide searching /
    >navigation tool-bar and an HTML wrapper, which includes the tool bar,
    >for plain-text files and directory listings.


    >If you wish to use Google to search the on-line stable release
    >documentation use "site:doc.ntp.org" in your search arguments.


    Yes, I went there to search on the word dynamic. I got junk.
    I finally tracked down by going from page to page from www.ntp.org
    See other post.

    Note that if you say the option is not implimented because it is the
    default, then the doc should say that. "does not support this option"
    does not mean the same as "implimented by default", although I can imagine
    arguments by a lawyer to say those statements are not mutually exclusive.




    >--
    >Steve Kostecke
    >NTP Public Services Project - http://support.ntp.org/


  17. Re: What happens if ntp server unavailable at start up?

    Bill,

    Unruh wrote:
    > Steve Kostecke writes:
    >
    >>On 2008-09-13, Joseph Gwinn wrote:

    >
    >>> Unruh wrote:
    >>>
    >>>> Harlan Stenn writes:
    >>>>
    >>>> >Unruh> Did the dynamic keyword ever work? The web docs say that it
    >>>> >Unruh> is not yet implimented.


    As already mentioned earlier, the keywaord "dynamic" had been introduced
    IIRC in 4.2.4. It lets ntpd retry if a server can not be reached initially.

    However, since the behaviour with the "dynamic" keyword is what users would
    normally expect ntpd to do I have proposed to make the "dynamic" behaviour
    the default and obsolete the "dynamic" keyword. Frank Kardel who had
    introduced the "dynamic" keyword agreed and implemented the proposed
    changes in ntp-dev 4.2.5p38 on 2007-05-26, and he also removed the
    description of the keyword from the HTML docs.

    Unfortunately Dave Mills who maintains the HTML docs at udel.edu did not
    pick up Frank's changes of the HTML docs. The file history for confopt.html
    shows that the description of the "dynamic" keyword has been re-added when
    confopt.html changes from Dave were pulled in again on 2007-07-23.

    I did a backport of Frank's changes for ntp-stable and I also modified the
    HTML docs and removed the description of the "dynamic" keyword. Those
    changes were picked up in 4.2.4p5.

    So if you use the stable version and have a look at the HTML docs which come
    with that version this should be OK.


    >>>> >I'm pretty sure it works - what documentation says it doesn't?
    >>>>
    >>>> Some document on ntp.org describing the options in the ntp.conf file.
    >>>> I do not want to look for it again-- the docs are incredibly hard to
    >>>> search-- one of the problems with making them into an infinite number
    >>>> of web pages.
    >>>
    >>> What I find useful is to use google with a "site:udel.edu" qualifier.
    >>>
    >>> It would help if the docs entire tree were under ntp.org though.

    >
    >>The documentation at http://www.eecis.udel.edu/~mills/ntp/html/ is the
    >>documentation for the current development snapshot of The NTP Reference
    >>Implementation (from www.ntp.org). This documentation may be correct
    >>for stable releases.

    >
    >>An archive of documentation for stable releases of The NTP Reference
    >>Implementation is located at http://doc.ntp.org/. This archive provides
    >>search capabilities powered by ht://dig.

    >
    >>The documentation contained in this archive is presented in its original
    >>form with the exception of the addition of a site-wide searching /
    >>navigation tool-bar and an HTML wrapper, which includes the tool bar,
    >>for plain-text files and directory listings.

    >
    >>If you wish to use Google to search the on-line stable release
    >>documentation use "site:doc.ntp.org" in your search arguments.

    >
    > Yes, I went there to search on the word dynamic. I got junk.


    Hm, I also tried this (searched for "dynamic site:doc.ntp.org") and got a
    couple of hits for 4.2.4, where the "dynamic" keyword is described for
    ntpdc and as "server option" in confopt.html.

    Since this refers to 4.2.4 but not 4.2.4p5 where it has been obsoleted this
    is absolutely correct, and I don't know why you would consider this as
    junk.

    Martin
    --
    Martin Burnicki

    Meinberg Funkuhren
    Bad Pyrmont
    Germany

  18. Re: What happens if ntp server unavailable at start up?

    Martin Burnicki writes:

    >Bill,


    >Unruh wrote:
    >> Steve Kostecke writes:
    >>
    >>>On 2008-09-13, Joseph Gwinn wrote:

    >>
    >>>> Unruh wrote:
    >>>>
    >>>>> Harlan Stenn writes:
    >>>>>
    >>>>> >Unruh> Did the dynamic keyword ever work? The web docs say that it
    >>>>> >Unruh> is not yet implimented.


    >As already mentioned earlier, the keywaord "dynamic" had been introduced
    >IIRC in 4.2.4. It lets ntpd retry if a server can not be reached initially.


    >However, since the behaviour with the "dynamic" keyword is what users would
    >normally expect ntpd to do I have proposed to make the "dynamic" behaviour
    >the default and obsolete the "dynamic" keyword. Frank Kardel who had
    >introduced the "dynamic" keyword agreed and implemented the proposed
    >changes in ntp-dev 4.2.5p38 on 2007-05-26, and he also removed the
    >description of the keyword from the HTML docs.


    >Unfortunately Dave Mills who maintains the HTML docs at udel.edu did not
    >pick up Frank's changes of the HTML docs. The file history for confopt.html
    >shows that the description of the "dynamic" keyword has been re-added when
    >confopt.html changes from Dave were pulled in again on 2007-07-23.


    >I did a backport of Frank's changes for ntp-stable and I also modified the
    >HTML docs and removed the description of the "dynamic" keyword. Those
    >changes were picked up in 4.2.4p5.


    >So if you use the stable version and have a look at the HTML docs which come
    >with that version this should be OK.


    I looked at the docs on the official site.




    >>>>> >I'm pretty sure it works - what documentation says it doesn't?
    >>>>>
    >>>>> Some document on ntp.org describing the options in the ntp.conf file.
    >>>>> I do not want to look for it again-- the docs are incredibly hard to
    >>>>> search-- one of the problems with making them into an infinite number
    >>>>> of web pages.
    >>>>
    >>>> What I find useful is to use google with a "site:udel.edu" qualifier.
    >>>>
    >>>> It would help if the docs entire tree were under ntp.org though.

    >>
    >>>The documentation at http://www.eecis.udel.edu/~mills/ntp/html/ is the
    >>>documentation for the current development snapshot of The NTP Reference
    >>>Implementation (from www.ntp.org). This documentation may be correct
    >>>for stable releases.

    >>
    >>>An archive of documentation for stable releases of The NTP Reference
    >>>Implementation is located at http://doc.ntp.org/. This archive provides
    >>>search capabilities powered by ht://dig.

    >>
    >>>The documentation contained in this archive is presented in its original
    >>>form with the exception of the addition of a site-wide searching /
    >>>navigation tool-bar and an HTML wrapper, which includes the tool bar,
    >>>for plain-text files and directory listings.

    >>
    >>>If you wish to use Google to search the on-line stable release
    >>>documentation use "site:doc.ntp.org" in your search arguments.

    >>
    >> Yes, I went there to search on the word dynamic. I got junk.


    >Hm, I also tried this (searched for "dynamic site:doc.ntp.org") and got a
    >couple of hits for 4.2.4, where the "dynamic" keyword is described for
    >ntpdc and as "server option" in confopt.html.


    >Since this refers to 4.2.4 but not 4.2.4p5 where it has been obsoleted this
    >is absolutely correct, and I don't know why you would consider this as
    >junk.


    The "junk" was irelevant hits ( about 20 of them to some refclock MX4200
    receiver, one to ntpc, The only relevant hit was one with a "relevance
    factor" or 1 star which was something like the 17th hit out of 23.

    That is what I call "junk". It often happens when googling I agree.
    Note I used the search on the doc.ntp.org main page, not a google search.


    >Martin
    >--
    >Martin Burnicki


    >Meinberg Funkuhren
    >Bad Pyrmont
    >Germany


  19. Re: What happens if ntp server unavailable at start up?

    Unruh wrote:
    > Martin Burnicki writes:
    >
    >>Bill,

    >
    >>Unruh wrote:
    >>> Steve Kostecke writes:
    >>>
    >>>>On 2008-09-13, Joseph Gwinn wrote:
    >>>
    >>>>> Unruh wrote:
    >>>>>
    >>>>>> Harlan Stenn writes:
    >>>>>>
    >>>>>> >Unruh> Did the dynamic keyword ever work? The web docs say that it
    >>>>>> >Unruh> is not yet implimented.

    >
    >>As already mentioned earlier, the keywaord "dynamic" had been introduced
    >>IIRC in 4.2.4. It lets ntpd retry if a server can not be reached
    >>initially.

    >
    >>However, since the behaviour with the "dynamic" keyword is what users
    >>would normally expect ntpd to do I have proposed to make the "dynamic"
    >>behaviour the default and obsolete the "dynamic" keyword. Frank Kardel who
    >>had introduced the "dynamic" keyword agreed and implemented the proposed
    >>changes in ntp-dev 4.2.5p38 on 2007-05-26, and he also removed the
    >>description of the keyword from the HTML docs.

    >
    >>Unfortunately Dave Mills who maintains the HTML docs at udel.edu did not
    >>pick up Frank's changes of the HTML docs. The file history for
    >>confopt.html shows that the description of the "dynamic" keyword has been
    >>re-added when confopt.html changes from Dave were pulled in again on
    >>2007-07-23.

    >
    >>I did a backport of Frank's changes for ntp-stable and I also modified the
    >>HTML docs and removed the description of the "dynamic" keyword. Those
    >>changes were picked up in 4.2.4p5.

    >
    >>So if you use the stable version and have a look at the HTML docs which
    >>come with that version this should be OK.

    >
    > I looked at the docs on the official site.


    As mentioned frequently on this page, the docs at www.ntp.org only refer to
    the ntp-dev version (in this case the online docs are not correct, though).

    [...]
    >>>>If you wish to use Google to search the on-line stable release
    >>>>documentation use "site:doc.ntp.org" in your search arguments.
    >>>
    >>> Yes, I went there to search on the word dynamic. I got junk.

    >
    >>Hm, I also tried this (searched for "dynamic site:doc.ntp.org") and got a
    >>couple of hits for 4.2.4, where the "dynamic" keyword is described for
    >>ntpdc and as "server option" in confopt.html.

    >
    >>Since this refers to 4.2.4 but not 4.2.4p5 where it has been obsoleted
    >>this is absolutely correct, and I don't know why you would consider this
    >>as junk.

    >
    > The "junk" was irelevant hits ( about 20 of them to some refclock MX4200
    > receiver, one to ntpc, The only relevant hit was one with a "relevance
    > factor" or 1 star which was something like the 17th hit out of 23.
    >
    > That is what I call "junk". It often happens when googling I agree.
    > Note I used the search on the doc.ntp.org main page, not a google search.


    How should a search engine know whether you are searching for the "dynamic"
    keyword or for the "Dynamic, 3D Nav" mode of an MX4200 refclock?

    If you select boolean search mode on docs.ntp.org and enter
    "dynamic and option"
    then there are much better hits.

    BTW, the search result of the ntpdc docs is correct since ntpdc also had to
    deal with the "dynamic" keyword.

    Martin
    --
    Martin Burnicki

    Meinberg Funkuhren
    Bad Pyrmont
    Germany

  20. Re: What happens if ntp server unavailable at start up?

    Martin Burnicki wrote:

    >
    > As mentioned frequently on this page, the docs at www.ntp.org only refer to
    > the ntp-dev version (in this case the online docs are not correct, though).
    >

    Rather than continually repeat this, why not arrange the documentation
    so that the documenation that is most likely to match user requirements
    is easiest to find, with a bias to making that for unsophisticated users
    easiest (e.g. Windows, easier that RHEL, and RHEL easier than general Unix).

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