UDP multicast packets not seen on listening interface in BETA5
rwatson at FreeBSD.org
Thu Sep 29 14:09:44 PDT 2005
On Thu, 29 Sep 2005, Josh Carroll wrote:
> I suspect maybe I am not properly joining the multicast group, so it's
> ignoring the packet. But like I said, this worked in BETA3 which is why
> I'm stumped.
Normally when you join a multicast group, IGMP messages will be sent on
the interface where it is joined. Could you confirm that messages are
sent in BETA3, and whether or not they are sent in BETA5?
When you subscribe to a multicast address, you do so on a particular
interface with a particular subscription. The multicast API allows you to
either use a default interface based on not specifying a particular
interface IP address, or allows you to specify an interface by IP address.
Could you tell me whether or not your application attempts to specify what
interface to use, and if there are other interfaces on the system that
(potentially) a multicast application might select instead?
If you use netstat -ia, it will show you all interfaces and current
multicast address subscriptions. Could you show me the entries for your
application running in BETA3, and any similar entries you can or cannot
find in BETA5?
Robert N M Watson
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