IGMP/Multicast Querier support?
reddit / freebsd

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FX-4450 · 2023-05-30 19:22

Does Freebsd support IGMP Querier mode? In Linux I do:

    $ echo -n 1 >
/sys/devices/virtual/net/br0/bridge/multicast_querier

This is to prevent floods on the network, I don't even need multicast.
But only snooping is not enough and our switches are simple/dumb(no
software switches but still with IGMP snooping implemented(TPLink)). I
am considering FBSD for next network server upgrade but I need this
functionality of querier to deal with floods(server to be able to
issue Membership queries).

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timvandijknl · 2023-05-30 19:26

There is  `net.inet.igmp.gsrdelay` , defaults to `10`. If more than
one GSR query is received in this time, it will be dropped.

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FX-4450 · 2023-05-30 19:39

Thank you but, I am not sure if this is supposed to do.

The thing is that some clients simply flood network with "asking for
querier" and need to be answered properly by querier, just dropping
packets on server will not do because its about other clients
connected to LAN who get flooded. I need server to explicitly issue
membership queries.

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timvandijknl · 2023-05-30 21:45

well in FreeBSD, interface briding is handled by the Dummynet
interface.. so you'd have to look at that for the specific function
you need: [https://man.freebsd.org/cgi/man.cgi?dummynet](https://man.f
reebsd.org/cgi/man.cgi?dummynet)

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FX-4450 · 2023-05-31 16:02

Unfortunately I have not found anything regarding this, also not in
the if\_bridge and ipfw man. I worry FBSD may simply not have this
functionality implemented. But without it I can't use it for my
server, as much as I would love to.