Configuring Interface-Level PIM Neighbor Policies

You can configure a policy to filter unwanted PIM neighbors. In the following example, the PIM interface compares neighbor IP addresses with the IP address in the policy statement before any hello processing takes place. If any of the neighbor IP addresses (primary or secondary) match the IP address specified in the prefix list, PIM drops the hello packet and rejects the neighbor.

If you configure a PIM neighbor policy after PIM has already established a neighbor adjacency with an unwanted PIM neighbor, the adjacency remains intact until the neighbor hold time expires. When the unwanted neighbor sends another hello message to update its adjacency, the router recognizes the unwanted address and rejects the neighbor.

To configure a policy to filter unwanted PIM neighbors:

1. Configure the policy. The neighbor policy must be a properly structured policy statement that uses a prefix list (or a route filter) containing the neighbor primary address (or any secondary IP addresses) in a prefix list and the reject option to reject the unwanted address.
   [edit]user@host# edit policy-optionsuser@host# set prefix-list nbrGroup 1 20.20.20.1/32user@host# set policy-statement nbr-policy from prefix-list nbrGroup1user@host# set policy-statement nbr-policy then reject
2. Configure the interface globally or in the routing instance. This example shows the configuration for the routing instance.
   [edit]user@host# edit routing-instances PIM.master protocols pimuser@host# set neighbor-policy nbr-policy
3. Verify the configuration by checking the Hello dropped on neighbor policy field in the output of the show pim statistics command.

Related Topics

• PIM Sparse Mode Overview
• Defining Routing Policies in the Policy Framework Configuration Guide
• show pim statistics in the Routing Protocols and Policies Command Reference