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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 a multicast group only from sources that have been approved by the organization.

Overview

Finding IDVersionRule IDIA ControlsSeverity
V-221139CISC-RT-000870SV-221139r999748_ruleCCI-002403medium
Description
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 groups hosts are allowed to join via IGMP or MLD.
STIGDate
Cisco NX OS Switch RTR Security Technical Implementation Guide2026-03-04

Related Frameworks

1 mapping across 3 frameworks
SCF0 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (2) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

NET-03Boundary Protection
0.50
NET-04.1Deny Traffic by Default & Allow Traffic by Exception
0.50
NIST 800-530 mappings

No source states a mapping between these directly.

Also reachable in 2 hops (8) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

CM-6Configuration Settings
1.00
SC-24Fail in Known State
1.00
SC-47Alternate Communications Paths
1.00
SC-5Denial-of-service Protection
1.00
SC-7Boundary Protection
1.00
SC-7(11)Restrict Incoming Communications Traffic
1.00
SC-7(29)Separate Subnets to Isolate Functions
1.00
SC-7(5)Deny by Default — Allow by Exception
1.00
CCI1 mapping
CCI-002403
1.00

Details

Check Text (C-221139r999748_chk)

Review the configuration of the DR to verify that it is filtering IGMP or MLD report messages, allowing hosts to only join multicast groups from sources that have been approved. Step 1: Verify that all host-facing interfaces are configured to filter IGMP Membership Report messages (IGMP joins) as shown in the example below: interface Ethernet2/4 no switchport ip address 10.2.22.3/24 ip pim sparse-mode ip igmp version 3 ip igmp report-policy ALLOWED_SOURCES Step 2: Verify that the report policy permits only sources that have been approved by the organization. route-map ALLOWED_SOURCES permit 10 match ip multicast source x.1.2.6/32 route-map ALLOWED_SOURCES permit 20 match ip multicast source x.1.2.7/32 route-map ALLOWED_SOURCES deny 30 match ip multicast source 0.0.0.0/0 Note: This requirement is only applicable to Source Specific Multicast (SSM) implementation. If the DR is not filtering IGMP or MLD report messages, this is a finding.

Fix Text (F-22843r409907_fix)

Step 1: Configure the report policy to filter IGMP Membership Report messages as shown in the example below: SW1(config-route-map)# route-map ALLOWED_SOURCES permit 10 SW1(config-route-map)# match ip multicast source x.1.2.6/32 SW1(config-route-map)# route-map ALLOWED_SOURCES permit 20 SW1(config-route-map)# match ip multicast source x.1.2.7/32 SW1(config-route-map)# route-map ALLOWED_SOURCES deny 30 SW1(config-route-map)# match ip multicast source 0.0.0.0/0 SW1(config-route-map)# exit Step 2: Apply the report policy to all applicable interfaces. SW1(config)# int e2/4 SW1(config-if)# ip igmp report-policy ALLOWED_SOURCES SW1(config-if)# end