Configuring a FW to Reject IGMP Packets Without the Router-Alert Option

If the multicast device connected to the user network segment needs to receive only the IGMP messages containing Router-Alert options, you can configure the multicast device to reject the IGMP messages without Router-Alert options. By default, the multicast device processes all the received IGMP messages.

Prerequisites

Before configuring a FW to reject IGMP packets without the Router-Alert option, complete the following task:

Configuring a unicast routing protocol
Configuring Basic IGMP Functions

Context

By default, FWs do not check the Router-Alert option contained in IGMP packets. That is, FWs process all the received IGMP packets, including the IGMP packets without the Router-Alert option.

When a user does not want to receive the IGMP packets without Router-Alert option, do as follows on the FW connected to the user:

The configuration involves the following cases:

Global configuration: It is valid on all interfaces.
Configuration on an interface: The configuration on an interface takes precedence over the global configuration. If the configuration on an interface is not done, the global configuration is used.

Procedure

Global Configuration
1. Access the system view.
  system-view
2. Access the IGMP view.
  igmp [ vpn-instance vpn-instance-name ]
3. Configure the FW to receive only the IGMP packets with the Router-Alert option.
  require-router-alert
  
  The IGMP packets without the Router-Alert option are discarded.
Configuration on an Interface
1. Access the system view.
  system-view
2. Access the interface view.
  interface interface-type interface-number
  
  The interface is connected to hosts or a switch.
3. Configure the interface to receive only the IGMP packets with the Router-Alert option.
  igmp require-router-alert
  
  The IGMP packets without the Router-Alert option are discarded.