PurposeCommand or Action
Example:
Switch# show ip pim rp
(Optional) Saves your entries in the configuration file.copy running-config startup-config
Step 10
Example:
Switch# copy running-config
startup-config
Related Topics
Auto-RP, on page 40
Example: Configuring Auto-RP, on page 72
Example: Defining the IP Multicast Boundary to Deny Auto-RP Information, on page 72
Example: Filtering Incoming RP Announcement Messages, on page 72
Preventing Join Messages to False RPs
Determine whether the ip pim accept-rp command was previously configured throughout the network by
using the show running-config privileged EXEC command. If the ip pim accept-rp command is not configured
on any device, this problem can be addressed later. In those routers or multilayer switches already configured
with the ip pim accept-rp command, you must enter the command again to accept the newly advertised RP.
To accept all RPs advertised with Auto-RP and reject all other RPs by default, use the ip pim accept-rp
auto-rp global configuration command.
If all interfaces are in sparse mode, use a default-configured RP to support the two well-known groups
224.0.1.39 and 224.0.1.40. Auto-RP uses these two well-known groups to collect and distribute RP-mapping
information. When this is the case and the ip pim accept-rp auto-rp command is configured, another ip pim
accept-rp command accepting the RP must be configured as follows:
Switch(config)# ip pim accept-rp 172.10.20.1 1
Switch(config)# access-list 1 permit 224.0.1.39
Switch(config)# access-list 1 permit 224.0.1.40
Related Topics
Example: Preventing Join Messages to False RPs, on page 73
Filtering Incoming RP Announcement Messages
You can add configuration commands to the mapping agents to prevent a maliciously configured router from
masquerading as a candidate RP and causing problems.
Catalyst 2960-XR Switch IP Multicast Routing Configuration Guide, Cisco IOS Release 15.0(2)EX1
OL-29426-01 55
Configuring PIM
Configuring a Rendezvous Point