[ntp:hackers] Further confirmation multicast broken
David L. Mills
mills at udel.edu
Sun Feb 27 08:21:54 PST 2005
Multicast doesn't work at all. Confirmation follows.
In principle, multicast with symmetric key should work. However, because
of the bug reported previously, the volley to calibrate the propagation
delay fails because the multicast address, rather than the unicast
address, is in dstadr in the association. See the behavior on howland,
which is receiving multicast from two servers. The first time the
multicast is received, the association is mobilized correctly. It sends
a client message to the server as expected. Somewhere between there and
the server response the dstadr is changed to the multicast address and
the volley fails.
I repeat. The dstadr is set correctly in newpeer(). It is not changed
anywhere else in ntp_peer.c or ntp_proto.c. Something, either in a macro
or in ntp_io.c is changing it. It should never be changed by anything
In principle, it would be possible to mobilize and continue the
assocation by including a novolley keyword on the multicast command in
the configuration file. Unfortunately, the syntax of that command can't
currently do that. The items following the multicast keyword must be
only group addresses.
More information about the hackers