SSDP Multicast vs. Bridge interface

[zone42]

I've set up a bridge interface with three members (one eth, two wifi interfaces).

Code: [Select]

ath0_wlan1: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> metric 0 mtu 1500
        ether 04:f0:21:2e:5d:a8
        inet6 fe80::6f0:21ff:fe2e:5da8%ath0_wlan1 prefixlen 64 scopeid 0x8
        groups: wlan
        ...
        status: running
        nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
ath1_wlan1: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> metric 0 mtu 1500
        ether 04:f0:21:2e:5d:1c
        inet6 fe80::6f0:21ff:fe2e:5d1c%ath1_wlan1 prefixlen 64 scopeid 0x9
        groups: wlan
        ...
        status: running
        nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
igb0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> metric 0 mtu 1500
        options=8520b8<VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,WOL_MAGIC,VLAN_HWFILTER,VLAN_HWTSO>
        ether 00:0d:b9:55:fa:8c
        inet6 fe80::20d:b9ff:fe55:fa8c%igb0 prefixlen 64 scopeid 0x1
        media: Ethernet autoselect (1000baseT <full-duplex>)
        status: active
        nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
bridge0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
        ether 02:02:e6:60:06:00
        inet 172.16.100.129 netmask 0xffffff00 broadcast 172.16.100.255
        inet6 2001:bf0:c080:403:: prefixlen 64
        id 00:00:00:00:00:00 priority 32768 hellotime 2 fwddelay 15
        maxage 20 holdcnt 6 proto rstp maxaddr 2000 timeout 1200
        root id 00:00:00:00:00:00 priority 32768 ifcost 0 port 0
        member: ath1_wlan1 flags=143<LEARNING,DISCOVER,AUTOEDGE,AUTOPTP>
                ifmaxaddr 0 port 9 priority 128 path cost 33333
        member: ath0_wlan1 flags=143<LEARNING,DISCOVER,AUTOEDGE,AUTOPTP>
                ifmaxaddr 0 port 8 priority 128 path cost 33333
        member: igb0 flags=143<LEARNING,DISCOVER,AUTOEDGE,AUTOPTP>
                ifmaxaddr 0 port 1 priority 128 path cost 20000
        groups: bridge
        nd6 options=1<PERFORMNUD>

Unfortunatly SSDP multicast messages (255.255.255.250 udp/1900) are not forwarded between the member interfaces. 

Is there a special setting/tunable needed for this?

[cookiemonster]

I am really not sure as I don't have this setup but you might want to see if you need to use the igmp proxy relay plugin.

[zone42]

IGMPproxy is a simple mulitcast router. But bridge0 is just one interface.

So this can't be the solution.

[zone42]

The problem seems to be similiar like in this older post: https://forum.netgate.com/topic/11349/upnp-bridged-interfaces/5

Unfortunately that thread ended without a solution. 

[zone42]

May be this bug: https://bugs.freebsd.org/bugzilla//show_bug.cgi?id=243554 ?

[zone42]

I think I found a clue after doing some sniffing on the affected interfaces.

SSDP NOTIFY multicast messages sent on the igb0 interface are apparently subject NAT. They arrive on the athX_wlan1 interfaces with the sender address of the WAN uplink.

However, the NAT rule for this network is an automatically generated one.

Presumably, the NAT is performed because the multicast address 239.255.255.250 does not clearly belong to the broadcast network of bridge0.

So the question is probably: How can this NAT be prevented?

[Patrick M. Hausen]

Switch NAT to "manual" and configure everything manually.

[zone42]

It's not pretty, but it works. 

[DesruX]

Switch NAT to "manual" and configure everything manually.

I think I have a similar issue. Multicast not propagating across my "LAN" network bridge.

how would a manual NAT configuration look like?