[ntp:questions] Reachable and rejected

David Woolley david at ex.djwhome.demon.co.uk.invalid
Fri Sep 12 21:00:04 UTC 2008


Dave Close wrote:
> dstadr=192.168.58.250, dstport=123, leap=00, stratum=2, precision=-7,

Precision -7 is poor, but possibly a contra-indication for the main 
hypothesis as I believe that w32time is normally even worse, at -6.

> rootdelay=0.000, rootdispersion=14089.630, refid=172.16.2.5, reach=377,

Root dispersion is excessive.  Combined with a stratum of 2, this is 
indicative of your using a w32time server rather than an NTP server. 
However, NAT should make no difference.  By any chance were the machines 
outside the NAT w32time clients, rather than NTP clients?

A real NTP server would not report root delay as zero unless it had a 
directly connected reference clock.  The reference ID indicates that 
that is not the case, and the stratum is suggestive that it isn't the 
case.  Again it looks as though you are not talking to an NTP server and 
probably talking to a w32time one.

What I think you can safely say is that you are not talking to an NTP 
server.

(Basically, the rootdispersion is telling you that the server hasn't had 
an update for so long that it can't be sure of its own time to better 
than 14 seconds.  NTP requires that, after adding extra errors for the 
hop to the client, that it know to better than one second.)

> unreach=0, hmode=3, pmode=4, hpoll=6, ppoll=6, flash=400 peer_dist,

peer_dist is telling you what I just said.

> keyid=0, ttl=0, offset=-51822.970, delay=2.200, dispersion=12.060,
> jitter=24.499, reftime=cc7533f1.d8de6ddf  Fri, Sep 12 2008 11:31:13.847,

reftime looks OK.  I wonder if the server is actually reflecting your 
rootdispersion.  Again, if so, not an NTP server.

> org=cc754459.c0418937  Fri, Sep 12 2008 12:41:13.751,
> rec=cc75448d.9bb36a6e  Fri, Sep 12 2008 12:42:05.608,
> xmt=cc75448d.9b19fbd7  Fri, Sep 12 2008 12:42:05.605,
> filtdelay=     2.34    2.64    4.18    3.24    2.71    2.40    2.93    2.20,
> filtoffset= -51856. -51847. -51849. -51851. -51844. -51838. -51840. -51822.,
> filtdisp=      7.81    8.76    9.72   10.69   11.65   12.63   13.59   14.56




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