xntpd related querries - NTP

This is a discussion on xntpd related querries - NTP ; Dear Sir/Madam I am a newbie to the ntp protocol. I read about this and try accumulate some aspect about it Please let me whether I am right or wrong. NTP is a protocol which helps in synchronising our system ...

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Thread: xntpd related querries

  1. xntpd related querries

    Dear Sir/Madam

    I am a newbie to the ntp protocol. I read about this and try accumulate
    some aspect about it
    Please let me whether I am right or wrong.

    NTP is a protocol which helps in synchronising our system clock with
    respect to a reference clock.

    So what I tried taken three system in a LAN which have all the xntpd
    installed in it. All the
    related utilities also present like ( ntpq , ntpdc etc..)

    Taken one system (say A (131.222.32.232) ) configured the ntp.conf
    file by putting one entry
    like :
    peer 131.222.32.3
    peer 131.222.32.229
    driftfile /etc/inet/ntp.drift

    Then other two systems has similarly ntp.conf file as follows :

    System B ( 131.222.32.3)

    server 131.222.32.232
    driftfile /etc/inet/ntp.drift

    System C (131.222.32.229)

    server 131.222.32.232
    driftfile /etc/inet/ntp.drift

    Then I started the deamon xntpd in the server with the debuging option
    on i.e. "-d".
    But I dont find the time of system B and C are not geting updated with
    that of System A ( server)
    The above assumption is mine. Because what I think System B and Sytem C
    will think Syetem A
    to be their server to update which it is not doing

    Any answer ????


  2. Re: xntpd related querries

    lulu wrote:
    > Dear Sir/Madam
    >
    > I am a newbie to the ntp protocol. I read about this and try accumulate
    > some aspect about it
    > Please let me whether I am right or wrong.
    >
    > NTP is a protocol which helps in synchronising our system clock with
    > respect to a reference clock.
    >
    > So what I tried taken three system in a LAN which have all the xntpd
    > installed in it. All the
    > related utilities also present like ( ntpq , ntpdc etc..)
    >
    > Taken one system (say A (131.222.32.232) ) configured the ntp.conf
    > file by putting one entry
    > like :
    > peer 131.222.32.3
    > peer 131.222.32.229
    > driftfile /etc/inet/ntp.drift
    >
    > Then other two systems has similarly ntp.conf file as follows :
    >
    > System B ( 131.222.32.3)
    >
    > server 131.222.32.232
    > driftfile /etc/inet/ntp.drift
    >
    > System C (131.222.32.229)
    >
    > server 131.222.32.232
    > driftfile /etc/inet/ntp.drift
    >
    > Then I started the deamon xntpd in the server with the debuging option
    > on i.e. "-d".
    > But I dont find the time of system B and C are not geting updated with
    > that of System A ( server)
    > The above assumption is mine. Because what I think System B and Sytem C
    > will think Syetem A
    > to be their server to update which it is not doing
    >
    > Any answer ????
    >


    I think you missed or misunderstood one very important point! NTP is
    intended to synchronizes clocks to UTC rather than to a "reference
    clock". The "reference clock" is generally a cesium frequency standard
    operated by a national standards laboratory. Access to this clock may
    be obtained via radio, telephone, or the internet.

    You seem to have told three systems, none of which knows what time it
    is, to get time from each other. Now there is a white paper from Sun
    Microsystems that suggests that three systems configured as peers will
    converge to a common, but not necessarily correct, time. I have not
    tried this and see no point to such an exercise.

    You need either a hardware reference clock such as a GPS timing
    receiver, HF receiver or VLF receiver capable or receiving a time signal
    broadcast from a national standards lab or at least one internet server
    that gets its time from such a clock.

  3. Re: xntpd related querries

    Thanks for your remark.
    I agreed to your point. But I want to know whether within these three
    system can i create
    a virtualisation that System A is a server for Sytem B and C and the
    time shown by System A should be updated by System B and C ( though it
    is the wrong time).

    I tried that to do by just changing the /etc/inet/ntp.conf file in
    case if Server by mentioning
    peers < IP ADDR- OF - B>
    peers

    and in clients
    server < IP ADDR-OF- A>

    this much only. But nothing change to the current time happening in
    client systems.
    But deamon showing packet transmission and "ntp -p" in server showing
    info about both the clients
    And below is the internal command peers to the utility xntpdc I applied
    and got the info as mentioned below :

    xntpdc> peers
    remote local st poll reach delay offset disp
    ==============================================
    +HOST1 5.0.0.0 16 64 0 0.00000 0.000000 16.0000
    +HOST2 5.0.0.0 16 64 0 0.00000 0.000000
    16.0000

    Here man page says if stratum the third feild ( st) is 16 then it is
    not sysnchonising with server.

    So is there anything else required to make a system behave as NTP
    server for some clients
    is the change in the config. file is not enough within a ISOLATED LAN
    ???


  4. Re: xntpd related querries


    lulu,

    Nothing at all will happen in your NTP network until the server, that
    is System A,
    is synchronized (as indicated by a "*" in the first column of the ntpq
    billboard).
    Systems B and C will not take their time from System A until System A
    indicates
    that it's sysnchronized.

    In order for System A to synchronize, it must have a time source to
    sync to.
    In your case, this will probably be localclock. You'll need an ntp.conf
    file
    something like

    server 127.127.1.1
    fudge 127.127.1.1 stratum 10
    driftfile /etc/inet/ntp.drift

    See also http://www.eecis.udel.edu/~mills/ntp...s/driver1.html

    Paul


  5. Re: xntpd related querries

    lulu wrote:
    > Thanks for your remark.
    > I agreed to your point. But I want to know whether within these three
    > system can i create
    > a virtualisation that System A is a server for Sytem B and C and the
    > time shown by System A should be updated by System B and C ( though it
    > is the wrong time).
    >
    > I tried that to do by just changing the /etc/inet/ntp.conf file in
    > case if Server by mentioning
    > peers < IP ADDR- OF - B>
    > peers
    >
    > and in clients
    > server < IP ADDR-OF- A>
    >
    > this much only. But nothing change to the current time happening in
    > client systems.
    > But deamon showing packet transmission and "ntp -p" in server showing
    > info about both the clients
    > And below is the internal command peers to the utility xntpdc I applied
    > and got the info as mentioned below :
    >
    > xntpdc> peers
    > remote local st poll reach delay offset disp
    > ==============================================
    > +HOST1 5.0.0.0 16 64 0 0.00000 0.000000 16.0000
    > +HOST2 5.0.0.0 16 64 0 0.00000 0.000000
    > 16.0000
    >
    > Here man page says if stratum the third feild ( st) is 16 then it is
    > not sysnchonising with server.
    >
    > So is there anything else required to make a system behave as NTP
    > server for some clients
    > is the change in the config. file is not enough within a ISOLATED LAN
    > ???
    >


    There is an "orphan mode" for use in isolated LANs. I've never needed
    it and don't know how it works. I believe it was added to ntpd v4.2 so
    you will need to install the latest version to get it. See the
    documentation for how it works, how to configure it, etc.

  6. Re: xntpd related querries

    Thanks Richard. thanks for the informations


  7. Re: xntpd related querries


    Hi Richard ,
    This time connected the system to the internet but it is through a
    proxy.
    And taken some public NTP server ( stratum -2) as a server for the
    System A.
    so inserted a line

    server

    But still it is not showing that it is synchronising to something.
    I think the proxy setting is not allowing to connect to that server.

    Is there any setting available in ntp.conf file to cross proxy with
    valid user name and passwd and reach to the startum-2 server .

    the xntpdc output shows when given with peers command as follows

    remote local st poll reach delay offset disp
    ================================================
    +HOST-1 5.0.0.0 16 64 0 0.00000 0.000000 16.0000
    +HOST-2 5.0.0.0 16 64 0 0.00000 0.000000
    16.0000
    =216.52.237.152 5.0.0.0 16 64 0 0.00000 0.000000 16.0000
    =216.52.237.151 5.0.0.0 16 64 0 0.00000 0.000000 16.0000

    below two are stratum-2 ip address.


  8. Re: xntpd related querries

    lulu wrote:

    > Hi Richard ,
    > This time connected the system to the internet but it is through a
    > proxy.
    > And taken some public NTP server ( stratum -2) as a server for the
    > System A.
    > so inserted a line
    >
    > server
    >
    > But still it is not showing that it is synchronising to something.
    > I think the proxy setting is not allowing to connect to that server.
    >
    > Is there any setting available in ntp.conf file to cross proxy with
    > valid user name and passwd and reach to the startum-2 server .
    >
    > the xntpdc output shows when given with peers command as follows
    >
    > remote local st poll reach delay offset disp
    > ================================================
    > +HOST-1 5.0.0.0 16 64 0 0.00000 0.000000 16.0000
    > +HOST-2 5.0.0.0 16 64 0 0.00000 0.000000
    > 16.0000
    > =216.52.237.152 5.0.0.0 16 64 0 0.00000 0.000000 16.0000
    > =216.52.237.151 5.0.0.0 16 64 0 0.00000 0.000000 16.0000
    >
    > below two are stratum-2 ip address.
    >


    I've never heard of anyone using NTP via a proxy. As far as I know, you
    must send a request to an NTP server and the server will send a reply.
    Your system must send at least five requests to the server and receive
    five replies before it can start disciplining your clock.

    I won't say that a proxy can't be used but I can't help you use one!

  9. Re: xntpd related querries

    >I've never heard of anyone using NTP via a proxy. As far as I know, you
    >must send a request to an NTP server and the server will send a reply.
    >Your system must send at least five requests to the server and receive
    >five replies before it can start disciplining your clock.


    I'm not sure what a proxy is for NTP. I know that NTP works through
    NAT, at least on my DSL modem. It wouldn't be hard to write some code
    that just relayed NTP packets.

    The usual solution if you have a firewall type machine in the way is to
    run ntpd on that machine and ask it directly. (You probably want ntpd
    running on it anyway so the times in your log files are accurate.)

    --
    These are my opinions, not necessarily my employer's. I hate spam.


  10. Re: xntpd related querries

    Hal Murray wrote:

    >>I've never heard of anyone using NTP via a proxy. As far as I know, you
    >>must send a request to an NTP server and the server will send a reply.
    >>Your system must send at least five requests to the server and receive
    >>five replies before it can start disciplining your clock.

    >
    >
    > I'm not sure what a proxy is for NTP. I know that NTP works through
    > NAT, at least on my DSL modem. It wouldn't be hard to write some code
    > that just relayed NTP packets.
    >
    > The usual solution if you have a firewall type machine in the way is to
    > run ntpd on that machine and ask it directly. (You probably want ntpd
    > running on it anyway so the times in your log files are accurate.)
    >


    I don't think that a proxy and a firewall are the same thing. I work
    through a NAT router/firewall without problems.

  11. Re: xntpd related querries

    "Richard B. Gilbert" wrote in message
    news:tvSdnTaQLYEi1frYnZ2dnUVZ_tidnZ2d@comcast.com. ..
    [...]
    > I don't think that a proxy and a firewall are the same thing. I work
    > through a NAT router/firewall without problems.


    So have I, and they aren't.

    A proxy is usually an application-level proxy, that processes and
    forwards traffic at a higher layer than the network layer. In a
    sense, NTP running on the firewall could be thought of as a proxy
    (but only in a sense).

    Groetjes,
    Maarten Wiltink



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