blocking multicast on layer 2 3750

Answered Question
Mar 23rd, 2009

I have a 3750-e, without routing or multicast enabled. there are two switch ports which uplink a firewall and router that are supporting multicast. How would one block multicast traffic on ports that don't need multicast and still support multicast, in this case, on the ports that do?

thanks, Kevin

Correct Answer by Jon Marshall about 7 years 11 months ago


IGMP snooping should be enabled by default. This is all you really need to meet your requirement -


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Overall Rating: 5 (1 ratings)
Jon Marshall Mon, 03/23/2009 - 14:54


Not entirely sure i understand what you are asking. Do you mean you want multicast packets to go through the switch but only on the relevant ports ?

If so you need to turn on IGMP snooping on the 3750-e switch.

If not please clarify.


ksvy_ksvy Mon, 03/23/2009 - 15:03

hi Jon, yes, correct

multicast isn't enabled, but I want to allow it only an couple ports. I found the "switchport block multicast" command, but my boss mentioned to make sure to use igmp snooping. What are the commands for these two options?

thanks, Kevin


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