Rule ID
SV-216636r1117236_rule
Version
V3R4
CCIs
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 router 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 10.1.28.8 remote-as 8 ip msdp sa-filter out 10.1.28.8 list OUTBOUND_MSDP_SA_FILTER 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 access-list extended OUTBOUND_MSDP_SA_FILTER deny ip 10.0.0.0 0.255.255.255 any permit ip any any If the router is not configured with an export policy to filter local source-active multicast advertisements, this is a finding.
Configure the router with an export policy avoid global visibility of local multicast (S, G) states. The example below will prevent exporting multicast active sources belonging to the private network. R8(config)#ip access-list extended OUTBOUND_MSDP_SA_FILTER R8(config-ext-nacl)#deny ip 10.0.0.0 0.255.255.255 any R8(config-ext-nacl)#permit ip any any R8(config-ext-nacl)#exit R8(config)#ip msdp sa-filter in x.1.28.2 list OUTBOUND_MSDP_SA_FILTER