Date: Fri, 1 Feb 2013 09:52:26 -0500 From: John Baldwin <jhb@freebsd.org> To: Tim Kientzle <tim@kientzle.com> Cc: freebsd-hackers@freebsd.org Subject: Re: Testing SIOCADDMULTI? Message-ID: <201302010952.26859.jhb@freebsd.org> In-Reply-To: <965B76D3-8BE8-4DA1-8A48-D22238490D03@kientzle.com> References: <AE65AFB2-A767-4457-B30A-007956A7D216@freebsd.org> <201301281109.24879.jhb@freebsd.org> <965B76D3-8BE8-4DA1-8A48-D22238490D03@kientzle.com>
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On Friday, February 01, 2013 1:23:26 am Tim Kientzle wrote: > >> Would still appreciate any suggestions for how to test these. > > > > You can write a simple app to listen for UDP packets and have it join a > > multicast group and have another machine on the same network write a packet to > > the multicast group. > > I tried this first, but the test program worked fine even > without ADDMULTI/DELMULTI support. Watching > tcpdump -e, it appears that IP4 multicast UDP uses > broadcast at the Ethernet layer. Were you running tcpdump? You have to use tcpdump -p to avoid putting the chip into promiscuous mode if so (promiscious causes the NIC to receive all multicast regardless of the filters assuming that your driver supports it correctly). -- John Baldwin
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