Check: CISC-L2-000170
Cisco NX OS Switch L2S STIG:
CISC-L2-000170
(in versions v2 r3 through v1 r1)
Title
The Cisco switch must have IGMP or MLD Snooping configured on all VLANs. (Cat III impact)
Discussion
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.
Check Content
Review the switch configuration to verify that IGMP or MLD snooping has been configured for IPv4 and IPv6 multicast traffic respectively. The example below are the steps to verify that IGMP snooping is enabled for each VLAN. Step 1: Verify that IGMP or MLD snooping is enabled globally. By default, IGMP snooping is enabled globally; hence, the following command should not be in the switch configuration: no ip igmp snooping Step 2: Verify that IGMP snooping is not disabled for any VLAN as shown in the example below: no ip igmp snooping vlan 11 Note: When globally enabled, it is also enabled by default on all VLANs, but can be disabled on a per-VLAN basis. If global snooping is disabled, VLAN snooping cannot be enabled. If global snooping is enabled, VLAN snooping cannot be enabled or disabled. If the switch is not configured to implement IGMP or MLD snooping for each VLAN, this is a finding.
Fix Text
Configure IGMP or MLD snooping for IPv4 and IPv6 multicast traffic respectively globally. SW1(config)# ip igmp snooping
Additional Identifiers
Rule ID: SV-220688r539671_rule
Vulnerability ID: V-220688
Group Title: SRG-NET-000512-L2S-000002
Expert Comments
CCIs
Number | Definition |
---|---|
CCI-000366 |
The organization implements the security configuration settings. |
Controls
Number | Title |
---|---|
CM-6 |
Configuration Settings |