216 | Internet Group Management Protocol (IGMP)
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IGMP Snooping Implementation Information
• IGMP snooping on the Dell Force 10 operating system (FTOS) uses IP multicast addresses not MAC 
addresses.
• IGMP snooping is not supported on stacked VLANs.
• IGMP snooping is supported on all MXL 10/40GbE stack members.
• IGMP snooping reacts to STP and MSTP topology changes by sending a general query on the interface 
that transitions to the forwarding state.
Configuring IGMP Snooping
Configuring IGMP snooping is a one-step process. That is, you enable it on a switch using the ip igmp 
snooping enable 
command from CONFIGURATION mode. 
To view the configuration, use the 
show running-config command from CONFIGURATION mode 
(Figure 12-6). To disable snooping for a VLAN, use the 
no ip igmp snooping command from INTERFACE 
VLAN mode.
Figure 12-6.  Enabling IGMP Snooping
Related Configuration Tasks
• Enabling IGMP Immediate-leave
• Disabling Multicast Flooding
• Specifying a Port as Connected to a Multicast Router
• Configuring the Switch as Querier
Enabling IGMP Immediate-leave
To configure the switch to remove a group-port association after receiving an IGMP Leave message, use 
the 
ip igmp fast-leave command from INTERFACE VLAN mode.
To view the configuration, use the 
show config command from INTERFACE VLAN mode (Figure 12-7).
Figure 12-7.  Enabling IGMP Snooping
FTOS(conf)#ip igmp snooping enable
FTOS(conf)#do show running-config igmp
ip igmp snooping enable
FTOS(conf)#
FTOS(conf-if-vl-100)#show config
!
interface Vlan 100
 no ip address
 ip igmp snooping fast-leave
 shutdown
FTOS(conf-if-vl-100)#