Re: ntpd problems on 3.5 connected via ADSL

[Uwe Dippel <udippel@uniten.edu.my>]

On Tue, 31 Aug 2004 13:43:00 -0700, Wolfgang S. Rupprecht wrote:

> udippel@uniten.edu.my (Uwe Dippel) writes:
>> On Tue, 31 Aug 2004 09:00:04 -0700, Wolfgang S. Rupprecht wrote:
>> 
>> > That code never worked well here on any obsd-current.  It would
>> > regularly lose sync.  Ignore it if you value your sanity.
>> 
>> I cannot real confirm this. On the machine with fixed IP it works very
>> well; though YMMV.
> 
> That version of NTP would keep time for a while and a few hour later
> I'd see many seconds of offset to all the references and ntpd would be
> slewing further and further from the correct time.
> 
>> > Here is what I run.  You can untar this in /usr/ports/localhacks and
>> > build and install just like an official port.
>> 
>> Would you mind to elaborate (or give a site) on the differences ?
> 
> One of the things that udel-ntpd regularly gets wrong is its loop
> filters.  Some releases just aren't stable.  While I understand some
> of the basic concepts of control theory, I'm not the right person to
> have eyeball the code and which changes fixed things.  All I can say
> is that I've been running the 4.2.0a version of udel-ntpd ever since I
> installed obsd on this machine in april.  Unlike the stock ports
> version it has been rock stable.
> 
>> Especially, would it solve the ADSL-problem as described in the OP ?
> 
> I have ADSL and the stock ports ntpd didn't work for me with what
> sounded like a similar failure.
> 
>> > (As an aside, if you need to get time from a machine running openbsd's
>> > ntpd, this probably won't work well.  Ntpd marks the obsd-ntpd machine
>> > as unacceptable and ignores it.)
>> 
>> Ignore ? I cannot confirm this either. A low stratum doesn't mean
>> 'unacceptable'.
>> I find my clients taking the time from the ntpd without problem. And
>> actually, as Theo mentioned, for the clients 50 msec of precision is more
>> than enough.
> 
> I have a network neighbor that uses the same ISP gateway as I do and
> he also runs openbsd.  We both have enhanced ADSL and he is a mere
> 20ms ping away from me.  My udel-ntpd alternates between marking his
> obsd-ntpd "insane", and just ignoring it altogether.
> 
> Currently he is >300ms off of real time with a >100ms jitter.
> 
>      remote           refid      st t when poll reach   delay   offset  jitter
> ==============================================================================
>  capsicum.wsrcc. .INIT.          16 u    - 1024    0    0.000    0.000 4000.00
> -ntp.sonic.net   63.192.96.10     2 u  880 1024  377   12.775    3.487   1.218
> -clepsydra.dec.c .GPS.            1 u  900 1024  377   28.544    7.961   5.354
> *nist1.aol-ca.tr .ACTS.           1 u  358  512  377   19.134   -0.159   2.504
> +clock.fmt.he.ne .GPS.            1 u  887 1024  377   29.885    4.091   2.215
> +clock.sjc.he.ne .CDMA.           1 u  883 1024  377   24.057    3.736   0.787
> -time.berkeley.n 216.152.68.20    2 u  888 1024  377   25.837    0.922  10.110
>  dumbcat.snafu.o 106.47.207.255   2 u  131  512  377   20.575  -307.52 106.990
>  mgm.mit.edu     .INIT.          16 u    - 1024    0    0.000    0.000 4000.00
>  LOCAL(0)        LOCAL(0)        10 l   21   64  377    0.000    0.000   0.008
> 
> 
> -wolfgang

Thanks a lot for your explanations ! I'll keep it in mind for my next free
time to test !

Uwe