[ntp:questions] NTS multicast response on IPv6

Danny Mayer mayer at ntp.isc.org
Wed Jan 18 18:13:57 UTC 2006

Mauricio Schramm wrote:
> Hi,
>     I'm trying to set up an NTP server that answers multicast requests from
> IPv6 clients without any success.

Please understand that is not how multicast works. The clients are
passive and only receive multicast packets from the server (modulo the
authentication keydance).

> I just don't know if the problem is with
> the client or with the server and I don't have a reliable test tool to make
> sure if any of them is correctly set. Does someone already tried this with
> success? I tried it with up to date Red Hat Linux and Free BSD and Open BSD
> servers and it never worked. Does someone know if I can use tools like ntpq
> to do my tests?

IPv4 and IPv6 multicast work in the latest ntp-dev release. Please note
however that you must set up authentication on both the client and the
server unless you explicitly disable authentication on the client.

> Do you know if something like that is supposed to work:
>     ntpq -n -c rv ff05::101
> or
>     ntpq -n -c rv ff01::101

This is wrong. ntpq can only request information about a specific host.


> Thanks,
> Mauricio

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