Why is there no built-in IGMP Snooping?

[inventor7777]

Hello OPNsense forum! I recently converted my old "WiFi-router" type network to a more modular firewall-router + AP system. The transition was extremely smooth and the features have been absolutely top-notch, and I'm very thankful for the open-source ethos which it radiates. However, one major modern networking function I noticed is missing - IGMP snooping.

OPNsense already supports IGMP itself, IGMP Proxy, and other multicast-related stuff, but there appears to be no way to configure it as a simple IGMP snooping querier for a LAN/VLAN?

Is this an intentional design decision, a limitation of FreeBSD, or simply an unimplemented feature? Many managed switches can act as queriers, but it seems like a natural fit for the gateway to provide this function.

I am aware that the general advice is to use a managed switch, but IMO it makes far more sense to run it on OPNsense because the configuration is already backed up, it has the highest-priority IP address, it's where I already keep track of other networking-related functions, and centralized management for all LANs.

I only noticed that it was missing when my ASUS XT8 (in AP mode, Gnuton's AsusWRT-Merlin .NG) elected itself quietly as the IGMP querier because OPNsense was not originating General Queries. That surprised me because the gateway is normally the logical device to provide this function, and I assumed OPNsense simply had to have it as it has everything else I need for my network.

[nero355]

IMHO there is no point in having this done by FreeBSD/OPNsense unless you have combined multiple NICs to one Bridge and that's something most people see as a bad practice ;)

You will always do the following :
OPNsense NIC => Switch Port => The rest of your network.

So just let the Switch(es) do it and let your Router do what it does best : Firewall/Routing/NAT/DHCP & DNS/VPN


The reason you think you need this is because your old "WiFi Router" basically did the same, but the connection from the Router to it's own built-in Switch was done on the internal side via the PCB of the whole device ;)

[inventor7777]

The reason you think you need this is because your old "WiFi Router" basically did the same, but the connection from the Router to it's own built-in Switch was done on the internal side via the PCB of the whole device ;)

😅 Yes, to some extent. Really though, it's because I always considered the OPNsense to be the main network administration device for basic LAN functions, because it has the best UI and it integrates with monitoring platforms very easily. Since OPNsense has other quality-of-life things like NGINX, TFTP, VMware, telegraf, etc, I assumed that IGMP querying isn't classified any differently.