Concept Guide

• IGMP snooping reacts to spanning tree protocol (STP) and multiple spanning tree protocol (MSTP) topology changes by sending a
general query on the interface that transitions to the forwarding state.
• If IGMP snooping is enabled on a PIM-enabled VLAN interface, data packets using the router as an Layer 2 hop may be dropped. To
avoid this scenario, Dell EMC Networking recommends that users enable IGMP snooping on server-facing end-point VLANs only.
Conguring IGMP Snooping
Conguring IGMP snooping is a one-step process. To enable, view, or disable IGMP snooping, use the following commands.
There is no specic conguration needed for IGMP snooping with virtual link trunking (VLT). For information about VLT congurations,
refer to
Virtual Link Trunking (VLT).
• Enable IGMP snooping on a switch.
CONFIGURATION mode
ip igmp snooping enable
• View the conguration.
CONFIGURATION mode
show running-config
• Disable snooping on a VLAN.
INTERFACE VLAN mode
no ip igmp snooping
Related Conguration Tasks
• Removing a Group-Port Association
• Disabling Multicast Flooding
• Specifying a Port as Connected to a Multicast Router
• Conguring the Switch as Querier
Example of ip igmp snooping enable Command
DellEMC(conf)#ip igmp snooping enable
DellEMC(conf)#do show running-config igmp
ip igmp snooping enable
DellEMC(conf)#
Removing a Group-Port Association
To congure or view the remove a group-port association feature, use the following commands.
• Congure the switch to remove a group-port association after receiving an IGMP Leave message.
INTERFACE VLAN mode
ip igmp fast-leave
• View the conguration.
INTERFACE VLAN mode
show config
Example of Conguration Output After Removing a Group-Port Association
DellEMC(conf-if-vl-100)#show config
!
interface Vlan 100
no ip address
Internet Group Management Protocol (IGMP)
381