Dell PowerEdge M805 - Manual (Page 601)

IGMP Commands 605
ip igmp router-alert-optional
Use the ip igmp router-alert-optional command to set IGMP to not require the Router-Alert field.
Syntax
ip igmp router-alert-optional
no ip igmp router-alert-optional
Default Value
The Router-Alert field is not required by default.
Command Mode
Global Configuration
Usage Guidelines
No specific guidelines
Example
ip igmp router-alert-optional