The Cisco ACI layer 2 switch must have Internet Group Management Protocol (IGMP) or Multicast Listener Discovery (MLD) snooping configured on all VLANs.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-272039 | CACI-L2-000011 | SV-272039r1113945_rule | CCI-000366 | low |
| Description | ||||
| IGMP and MLD snooping provides a way to constrain multicast traffic at layer 2. By monitoring the IGMP or MLD membership reports sent by hosts within a VLAN, the snooping application can set up Layer 2 multicast forwarding tables to deliver specific multicast traffic only to interfaces connected to hosts interested in receiving the traffic, thereby significantly reducing the volume of multicast traffic that would otherwise flood the VLAN. | ||||
| STIG | Date | |||
| Cisco ACI Layer 2 Switch Security Technical Implementation Guide | 2025-06-13 | |||
Details
Check Text (C-272039r1113945_chk)
Verify the switch configuration enables IGMP or MLD snooping for IPv4 and IPv6 multicast traffic. Below is an example of the steps to verify that IGMP snooping is enabled for each VLAN:
apic1(config-tenant-template-ip-igmp-snooping)# show run all
If the switch is not configured to implement IGMP or MLD snooping for each VLAN, this is a finding.
Fix Text (F-75996r1063513_fix)
Configure IGMP or MLD snooping for IPv4 and IPv6 multicast traffic respectively globally.
Example:
apic1(config-tenant)# template ip igmp snooping policy <policy name>