You can configure a policy filter to control the flow of SA messages going to or coming from an MSDP peer. For example, policy filters can help mitigate state explosion during denial of service (DoS) or other attacks by limiting what is propagated to other domains using MSDP.
entry policy2 { if match any{ nlri 10.10.10.0/24; } then { deny; } } entry policy1 { if match any{ nlri 10.10.10.0/24; nlri 20.20.20.0/24 ; } <= permit these sources then { permit; } }