[ntp:questions] Re: NTP over multicast sat link with no return channel
mayer at ntp.isc.org
Tue Apr 11 02:32:12 UTC 2006
juliansomers at googlemail.com wrote:
> Thanks for the replies,
> I think I now have the server sending the multicast correctly, using
> broadcast 220.127.116.11 ttl 2
> I see the packets coming over the satellite using tcpdump:
> 22:50:05.750313 IP 192.168.1.2.123 > 18.104.22.168.123: NTPv4 bcast, strat
> 3, poll 6, prec -20
> Im running ntpd on the client with this config:
> driftfile /var/lib/ntp/ntp.drift
> restrict default nomodify nopeer
> restrict 127.0.0.1
> multicastclient 22.214.171.124
> disable auth
> It seems that ntpd is listening to the multicast:
> root # netstat -na | grep 126.96.36.199
> udp 0 0 188.8.131.52:123 0.0.0.0:*
> but I don't see the peer come up on he client when I go:
> root # ntpq -pn
> No association ID's returned
> Should I see it as a peer?
You should give it long enough. Broadcast/Multicast packets are sent
every 64 seconds and that never changes, unlike regular associations.
What version of ntp are you running? You need to use a recent version as
earlier versions were badly broken in multiple places.
> I did not expect to see 184.108.40.206 on the server as a peer:
> water root # ntpq -pn
> remote refid st t when poll reach delay offset
>> 220.127.116.11 .MCST. 16 u - 64 0 0.000 0.000
> Does this look correct?
Yes, that's normal.
> Danny, you said,
>> You can disable auth in the client by adding disable auth to the config
>> file. You would need to do it for your case.
> does this mean that if I disable auth, the client will not try to
> contact the server for authentication, and so there is not a need for
You cannot specify novolley for multicast, it's not supported.
> many thanks for your time,
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