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CISC-RT-000860 - 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.

Information

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.

NOTE: Nessus has provided the target output to assist in reviewing the benchmark to ensure target compliance.

Solution

Configure the DR to filter the IGMP or MLD Membership Report messages to allow hosts to join only those multicast groups that have been approved.

Step 1: Configure the report policy to filter IGMP Membership Report messages as shown in the example below:

SW1(config)# route-map ALLOWED_GROUPS permit
SW1(config-route-map)# match ip multicast group 233.1.1.0/24
SW1(config-route-map)# route-map ALLOWED_GROUPS permit 20
SW1(config-route-map)# match ip multicast group 233.1.1.0/32
SW1(config-route-map)# route-map ALLOWED_GROUPS permit 30
SW1(config-route-map)# match ip multicast group 233.1.1.1/32
SW1(config-route-map)# route-map ALLOWED_GROUPS deny 40
SW1(config-route-map)# match ip multicast group 224.0.0.0/4
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_GROUPS
SW1(config-if)# end

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Cisco_NX-OS_Switch_Y26M04_STIG.zip

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-7(11), CAT|III, CCI|CCI-002403, Rule-ID|SV-221138r999747_rule, STIG-ID|CISC-RT-000860, STIG-Legacy|SV-111169, STIG-Legacy|V-102213, Vuln-ID|V-221138

Plugin: Cisco

Control ID: 8ab5021a637686e72aa6091a7fc05cdf71628fb8ce85986b81cd84e0e5b40dd1