Information
PIM Accept-RP allows administrators to restrict which multicast groups a rendezvous point (RP) serves in a PIM sparse mode domain. By default, an RP accepts all multicast groups in the 224.0.0.0/4 range. Using an access list (ACL), this feature limits join/prune message processing to specific multicast groups, enhancing control and reducing unnecessary traffic.
Without restrictions, an RP processes join/prune messages for all multicast groups in the default Class D range, leading to potential resource waste and security risks. PIM Accept-RP, configured with an ACL, ensures the RP handles only authorized multicast groups, preventing unwanted traffic and optimizing network operations.
Solution
Configuration to enable PIM Accept RP ACL -
switch(config)# access-list ip <pim_rp_grp_acl>
switch(config-acl-ip)# 10 permit any any <225.1.1.2/255.255.255.0>
switch(config-acl-ip)# 20 permit any any <239.1.1.2/255.255.255.0>
switch(config)-acl-ip# exit
switch(config)# router pim
switch(config-pim)# accept-rp <30.1.1.1> access-list <pim_rp_grp_acl>
switch(config-pim)# exit
switch(config)# access-list ip <pim_rpv6_grp_acl>
switch(config-acl-ipv6)# 10 permit any any <ff2e::2/64>
switch(config-acl-ipv6)# 20 permit any any <ff1e::1/64>
switch(config-acl-ipv6)# exit
switch(config)# router pim6
switch(config-pim6)# accept-rp <30::1> access-list <pim_rpv6_grp_acl>
switch(config-pim6)# exit
Impact:
The feature improves multicast efficiency and security by filtering out unauthorized groups. Permitted groups are processed as usual, while unwanted traffic is ignored. This targeted control reduces resource consumption and limits the risk of malicious or unnecessary multicast activity.
Item Details
Category: ACCESS CONTROL, SECURITY ASSESSMENT AND AUTHORIZATION, MEDIA PROTECTION, SYSTEM AND COMMUNICATIONS PROTECTION
References: 800-53|AC-3, 800-53|AC-5, 800-53|AC-6, 800-53|CA-7, 800-53|MP-2, 800-53|SC-4, CSCv7|14.6, CSCv7|14.7
Control ID: 3846f0db5ca3d267f319f53f6249df6cdb14320d23a7a75c347fb250e5cfef3a