IGMP Snooping without Router

Hi NL Team,

Does the attached look like a “healthy” debug from an IGMP debug. This was taken from the “querier”. It is a multicast environment with no Layer 3 router as such. I see there seems to be V2 and V3 messages also. Is there anything there that looks of immediate concern?

Output.txt (7.9 KB)

Hi Robert,

Looks OK to me. The “Report has illegal group address” messages that you see are normal. The 224.x.x.x range is link-local multicast so these are ignored.



I have a problem in real life with igmp. I have two host that send imgp version 3 between two diferent interfaces VLAN (SVI) they need to see igmp version 3 each other. With the command ip igmp snooping querier will hosts see the igmp version 3 eventhough they are in separate VLANs and broadcast domain?

Thank you!!

Hello Carlo

If you have a setup where you have two VLANs and you require routing between them, then IGMP Snooping without a Router is not a solution for this. These solutions are only for scenarios with a single VLAN.

The ip igmp snooping querier command will make the SVI port of a switch a querier, but it will not be able to route IGMP messages to other VLANs, but the will remain only within the specific broadcast domain. If you have such a scenario, it is better to go for using a multicast router since you need the routing functionality.

I hope this has been helpful!


1 Like

Thank you !
This works