[SOLVED] How to get multicast/IGMP working via 2 separate NICs bridged together?

Started by sharkymcdongles, February 20, 2024, 02:21:40 PM

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So I followed the guide here:

https://docs.opnsense.org/manual/how-tos/lan_bridge.html

I created a LAN1 on re0 and a LAN2 on re1 with no IPs assigned as instructed.

I then created a bridge interface and assigned LAN1 and LAN2 to it.

I then create a new interface called LAN and assigned bridge0 to it with a Static IPv4.

I also set the tunables as documented in the above link.

Everything works fine except for IGMP going between the LAN1 and LAN2. I tried allowing IGMP on LAN1, LAN2, and the bridge LAN. This  didn't work.

I then installed MDNS repeater, and I could get it to work by selecting WAN and LAN as my interfaces. This isn't ideal though as I don't want my IGMP to go over WAN at all.

When I try and select LAN1 and LAN2 as my MDNS repeater interfaces it fails to bind and says it is already bound because I guess LAN1 and LAN2 have no IPs.

Is there any way to get multicast working without having WAN on the repeater?


I'm sorry, but, use a switch.

Apart from that, if two interfaces are bridged, you should not need a mdns repeater. That's only for routed networks.

If you did indeed configure the bridge members without an IP address and the IP address on the bridge and all the tunables, then multicast should "just work".

One would have to look on your machine with tcpdump what is actually happening.
Deciso DEC750
People who think they know everything are a great annoyance to those of us who do. (Isaac Asimov)

Thanks so much for the reply guys. I assumed it would just work too. I do have a switch, but I wanted to use the 2 NICs on my ethernet card since I have it centrally in my flat and the two go to separate rooms and a switch won't fit in the utility box alongside the router. Any and all help is much appreciated.

Should I take a dump on the Opnsense router or one of the devices on the NIC?

Here are pictures of my setup if anyone would be so kind as to tell me where I am failing:

https://imgur.com/a/tU5CMTi

Also happy to provide anything else or take tcp dumps.

The problem was the domain name I chose was .local for the domain name under general settings. I didn't see the warning when I created the domain name only after the fact.