The Cisco multicast Designated switch (DR) must be configured to filter the Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) Report messages to allow hosts to join only multicast groups that have been approved by the organization.
An XCCDF Rule
Description
<VulnDiscussion>Real-time multicast traffic can entail multiple large flows of data. Large unicast flows tend to be fairly isolated (i.e., someone doing a file download here or there), whereas multicast can have broader impact on bandwidth consumption, resulting in extreme network congestion. Hence, it is imperative that there is multicast admission control to restrict which multicast group's hosts are allowed to join via IGMP or MLD.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-220464r864160_rule
- Severity
- Low
- References
- Updated
Remediation - Manual Procedure
Configure the DR to filter the IGMP or MLD Membership Report messages to allow hosts to join only multicast groups that have been approved.
Step 1: Configure the ACL to filter IGMP Membership Report messages as shown in the example below:
SW2(config)#ip access-list standard IGMP_JOIN_FILTER
SW2(config-std-nacl)#deny 239.8.0.0 0.0.255.255