Rule ID
SV-221145r1137902_rule
Version
V3R4
CCIs
CCI-001368
To avoid global visibility of local information, there are a number of source-group (S, G) states in a PIM-SM domain that must not be leaked to another domain, such as multicast sources with private address, administratively scoped multicast addresses, and the auto-RP groups (224.0.1.39 and 224.0.1.40). Allowing a multicast distribution tree, local to the core, to extend beyond its boundary could enable local multicast traffic to leak into other autonomous systems and customer networks.
Review the switch configuration to determine if there is export policy to block local source-active multicast advertisements. Step 1: Verify that an outbound source-active filter is bound to each MSDP peer as shown in the example below: ip msdp peer x.1.28.2 connect-source Ethernet2/1 remote-as nn ip msdp sa-policy x.1.28.2 prefix-list OUTBOUND_MSDP_SA_FILTER out Step 2: Review the access lists referenced by the source-active filters and verify that MSDP source-active messages being sent to MSDP peers do not leak advertisements that are local. ip prefix-list OUTBOUND_MSDP_SA_FILTER seq 10 deny 10.0.0.0/8 le 32 ip prefix-list OUTBOUND_MSDP_SA_FILTER seq 20 permit 0.0.0.0/0 ge 8 If the switch is not configured with an export policy to filter local source-active multicast advertisements, this is a finding.
Configure the switch with an export policy to avoid global visibility of local multicast (S, G) states. The example below will prevent exporting multicast active sources belonging to the private network. SW1(config)# ip prefix-list OUTBOUND_MSDP_SA_FILTER seq 10 deny 10.0.0.0/8 le 32 SW1(config)# ip prefix-list OUTBOUND_MSDP_SA_FILTER seq 20 permit 0.0.0.0/0 ge 8 SW1(config)# exit SW1(config)# ip msdp sa-policy x.1.28.2 prefix-list OUTBOUND_MSDP_SA_FILTER out SW1(config)# end