Multicast/SSDP not working (on VLAN interface)

[Rodney W. Grimes]

> Dear List
> 
> I was unfortunately unable to find a way to search this mailing list's 
> archive; so please bear with me if the question was answered before.

google:  site:freebsd.org Then what you are searching for

is one way to search all of freebsd.org for what you are seeking.
> 
> My goal is to have DLNA clients (VLC, Heos music system, ...) in 
> multiple networks discover a MiniDLNA server.
> 
> The server shows up in VLC when it starts (or is restarted) after VLC is 
> running. If the server is already running when VLC is started, VLC does 
> not detect/find the server.
> 
> Very much like this source states:
> https://sourceforge.net/p/minidlna/bugs/94/#8c8f
> I suspect a problem with the M-SEARCH messages the client is sending.
> 
> Using tcpdump on the interface where M-SEARCH from VLC are coming in, I 
> can indeed see the packets/messages arrive (they are sent from the 
> client to 239.255.255.250). So it is is not a router or switch or 
> whatever blocking the packets.
> 
> Now, if I (manually) add a static route for 224.0.0.0/4 via the 
> interface the M-SEARCH messages are coming in, everything starts to work!
> 
> route add -net 224.0.0.0/4 -iface re1.32
> 
> The (main) problem here is that I have multiple networks with clients in 
> them. So a static route does not REALLY solve my problem.
> 
> Also I do not (yet?) understand why the route should be required.
> 
> What I see is that ifmcstat -f inet -i re1.32 does not list a membership 
> for 239.255.255.250 when it is not working, but does list the membership 
> when it is working...
> 
> So I suspect that "something" is dropping the M-SEARCH packets for some 
> reason after they are received. And I cannot get rid of the feeling that 
> it has something to do with the fact that the incoming interface is a 
> VLAN interface...
> My first guess, anti spoofing, seems not to be the problem (I am using 
> ipfw and "not antispoof in" but that does not seem to drop any traffic).

Are you running with "firewall_type="simple""?
If so it is set to block all 224/4 packets, see this part
of /etc/rc.firewall:
        # And stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1,
        # DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E)
        # on the outside interface
        ${fwcmd} table ${BAD_ADDR_TBL} add 0.0.0.0/8
        ${fwcmd} table ${BAD_ADDR_TBL} add 169.254.0.0/16
        ${fwcmd} table ${BAD_ADDR_TBL} add 192.0.2.0/24
        ${fwcmd} table ${BAD_ADDR_TBL} add 224.0.0.0/4
        ${fwcmd} table ${BAD_ADDR_TBL} add 240.0.0.0/4

	${fwcmd} add deny all from any to "table($BAD_ADDR_TBL)" via ${oif}

Your route effected this as your packets are no longer trying to
use an all interfaces path, but a specific interface, and that is
probably not ${oif} of your firewall.

> 
> Do I miss something obvious or can someone point me in the right direction?

Probably just remove the 224.0.0.0/4 from the above table and
things may start to work.

> 
> VLC v2.2.8 is running on Mac OSX 10.12. MiniDLNA v1.2.1,1 is running on 
> FreeBSD RELEASE-11.1.
> 
> More information can be found in the FreeBSD forum [1].
> 
> 
> Thanks heaps
> andreas
> 
> [1] 
> https://forums.freebsd.org/threads/minidlna-not-discovered-multicast-issue.64947/
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-- 
Rod Grimes                                                 rgrimes at freebsd.org