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2524 & IGMP question

Stuart Teo
Trusted Contributor

2524 & IGMP question

If I issued an 'ip igmp block' command to a port, does it block only inbound or does it also block outbound multicast traffic?
If a problem can be fixed, there's nothing to worry. If a problem can't be fixed, worrying ain't gonna help. Bottom line: don't worry.
3 REPLIES
Jerome Henry
Honored Contributor

Re: 2524 & IGMP question

Hi,

Bloacking igmp will prevent multicast traffic to be flooded thru that port, in outbound way. But the decision to flood is made after port has transmitted to the ship, that is to say, in most cases (except specific multicat address structure), inbound won't be blocked.
Good idea is to apply this command to all ports, especially the pruning ones.

hth

J
You can lean only on what resists you...
Stuart Teo
Trusted Contributor

Re: 2524 & IGMP question

I couldn't do that. (block all ports)

The devices on all the port (except the uplink port) need to be able to see the multicast group. However, I do not want those traffic to be transmitted out of the uplink port.

I thought that by blocking the uplink port would do the trick but I'm still seeing subscribes at my routers. Sigh.
If a problem can be fixed, there's nothing to worry. If a problem can't be fixed, worrying ain't gonna help. Bottom line: don't worry.
Stuart Teo
Trusted Contributor

Re: 2524 & IGMP question

hp support stated that the block command should block both incoming and outgoing multicast groups excluding some specific groups like all routers, bpdu, etc.
If a problem can be fixed, there's nothing to worry. If a problem can't be fixed, worrying ain't gonna help. Bottom line: don't worry.