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ARST-RT-000670 - The Arista multicast Designated Router (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.

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 Arista DR to filter the IGMP and MLD report messages to allow hosts to join only multicast groups from sources that have been approved.

Step 1: Configure the ACL to filter the unauthorized IGMP groups.

LEAF-1A(config-if-Et3)#ip access-list standard ALLOWED_SOURCES
LEAF-1A(config-std-acl-ALLOWED_SOURCES)# 10 permit 232.0.0.0/8
LEAF-1A(config-std-acl-ALLOWED_SOURCES)# 20 deny any log

Step 2: Configure the IGMP filter in IGMP process.

LEAF-1A(config)#router pim sparse-mode
LEAF-1A(config-router-pim-sparse)# ipv4
LEAF-1A(config-router-pim-sparse-ipv4)# ssm range ALLOWED_SOURCES

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Arista_MLS_EOS_4-X_Y25M07_STIG.zip

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-7(11), CAT|II, CCI|CCI-002403, Rule-ID|SV-256046r882480_rule, STIG-ID|ARST-RT-000670, Vuln-ID|V-256046

Plugin: Arista

Control ID: 1f777875f8fb5b8d948868729d7e057ee3107ac1466d70e395d777005c570fd4