[ntp:questions] refid on client differs from refid on local server
Danny Mayer
mayer at ntp.isc.org
Fri Dec 16 03:01:37 UTC 2005
Nigel Henry wrote:
> With a bit of help from Danny in commenting out restrict lines, I now have NTP
> working well with my 2 Linux servers and multiple Linux clients on the other
> machine. One small query is. The refid's on the client distro's, when running
> ntpq> pe show the original IP address, as on the website for the stratum 2
> servers, but the refid IP addresses on my server ,are different. Why is this
> so? Also the other distro I use as a server (FC1) just shows alternative
> hostnames under refid for the same servers. Admittadly FC1 is using a
> slightly earlier version of NTP. A few details below, and the relevant ntpq>
> pe outputs below that.
>
> FC2-server is using ntp-4.2.0-7
> FC1-server is using ntp-4.1.2-5
> FC2-client (as an example, as I have many clients) is using ntp-4.2.0-7
>
> This is the ntpq> pe for the FC2 server
>
> ntpq> pe
> remote refid st t when poll reach delay offset jitter
> ==============================================================================
> +lptfpc46.obspm. 195.220.94.163 2 u 89 128 377 136.809 3.547 175.646
> *ntp.kamino.fr 193.52.184.106 2 u 101 128 377 287.905 1.165 59.055
> +ntp2.belbone.be 195.13.23.250 2 u 99 128 377 142.793 -62.327 53.907
> ntpq>
>
> This is the ntpq> pe for the FC2 client. One of many clients on this machine
>
> ntpq> pe
> remote refid st t when poll reach delay offset jitter
> ==============================================================================
> *192.168.0.230 216.32.94.18 3 u 79 128 377 0.422 32.474 8.907
> 192.168.0.228 .INIT. 16 u - 1024 0 0.000 0.000 4000.00
> ntpq>
>
> This is the ntpq> pe for the FC1 server, on the same machine as the FC2
> server, but showing alternative hostnames, rather than IP addresses under
> refid
>
> ntpq> pe
> remote refid st t when poll reach delay offset jitter
> ==============================================================================
> *lptfpc46.obspm. horlogegps.rese 2 u 106 128 377 128.493 -51.345 0.757
> +ntp.kamino.fr saturne.obs-bes 2 u 104 256 377 279.962 -70.196 7.481
> +ntp2.belbone.be ntp0.belbone.be 2 u 44 256 377 135.129 -61.765 0.378
> ntpq> pe
>
> None of this is any big deal as NTP appears to be working very well and all my
> clocks are synched, but I would like to have an explanation to my query.
> Nigel.
Sigh. Please repeat after me: A refid is NOT an IP address, it's a
32-bit number that is used for loop prevention.
It was a mistake to allow it to be translated into a host name or
display it as anything but a hex number. Things get much worse with IPv6
where the refid looks like an IPv4 address but is in fact a mangled IPv6
address MD5 hash. I've been trying to pursuade Dave to agree to change
the display format at least in the beginning.
Danny
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