[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



More information about the questions mailing list